CINXE.COM

<!DOCTYPE html> <html class="client-nojs vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-sticky-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-toc-available" lang="en" dir="ltr"> <head> <meta charset="UTF-8"> <title>Hierarchy of evidence - Wikipedia</title> <script>(function(){var className="client-js vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-sticky-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-toc-available";var cookie=document.cookie.match(/(?:^|; )enwikimwclientpreferences=([^;]+)/);if(cookie){cookie[1].split('%2C').forEach(function(pref){className=className.replace(new RegExp('(^| )'+pref.replace(/-clientpref-\w+$|[^\w-]+/g,'')+'-clientpref-\\w+( |$)'),'$1'+pref+'$2');});}document.documentElement.className=className;}());RLCONF={"wgBreakFrames":false,"wgSeparatorTransformTable":["",""],"wgDigitTransformTable":["",""],"wgDefaultDateFormat":"dmy", "wgMonthNames":["","January","February","March","April","May","June","July","August","September","October","November","December"],"wgRequestId":"8d75d4e1-a14b-4303-8f29-1bb4f38dbbc9","wgCanonicalNamespace":"","wgCanonicalSpecialPageName":false,"wgNamespaceNumber":0,"wgPageName":"Hierarchy_of_evidence","wgTitle":"Hierarchy of evidence","wgCurRevisionId":1243995306,"wgRevisionId":1243995306,"wgArticleId":4521155,"wgIsArticle":true,"wgIsRedirect":false,"wgAction":"view","wgUserName":null,"wgUserGroups":["*"],"wgCategories":["All articles with dead external links","Articles with dead external links from September 2017","Articles with permanently dead external links","Articles with short description","Short description matches Wikidata","All articles with unsourced statements","Articles with unsourced statements from November 2023","Wikipedia articles needing clarification from March 2018","Wikipedia articles incorporating text from the National Cancer Institute Dictionary of Cancer Terms", "Evidence","Evidence-based practices","Research","Clinical research"],"wgPageViewLanguage":"en","wgPageContentLanguage":"en","wgPageContentModel":"wikitext","wgRelevantPageName":"Hierarchy_of_evidence","wgRelevantArticleId":4521155,"wgIsProbablyEditable":true,"wgRelevantPageIsProbablyEditable":true,"wgRestrictionEdit":[],"wgRestrictionMove":[],"wgNoticeProject":"wikipedia","wgCiteReferencePreviewsActive":false,"wgFlaggedRevsParams":{"tags":{"status":{"levels":1}}},"wgMediaViewerOnClick":true,"wgMediaViewerEnabledByDefault":true,"wgPopupsFlags":0,"wgVisualEditor":{"pageLanguageCode":"en","pageLanguageDir":"ltr","pageVariantFallbacks":"en"},"wgMFDisplayWikibaseDescriptions":{"search":true,"watchlist":true,"tagline":false,"nearby":true},"wgWMESchemaEditAttemptStepOversample":false,"wgWMEPageLength":40000,"wgRelatedArticlesCompat":[],"wgCentralAuthMobileDomain":false,"wgEditSubmitButtonLabelPublish":true,"wgULSPosition":"interlanguage","wgULSisCompactLinksEnabled":false, "wgVector2022LanguageInHeader":true,"wgULSisLanguageSelectorEmpty":false,"wgWikibaseItemId":"Q17135794","wgCheckUserClientHintsHeadersJsApi":["brands","architecture","bitness","fullVersionList","mobile","model","platform","platformVersion"],"GEHomepageSuggestedEditsEnableTopics":true,"wgGETopicsMatchModeEnabled":false,"wgGEStructuredTaskRejectionReasonTextInputEnabled":false,"wgGELevelingUpEnabledForUser":false};RLSTATE={"ext.globalCssJs.user.styles":"ready","site.styles":"ready","user.styles":"ready","ext.globalCssJs.user":"ready","user":"ready","user.options":"loading","ext.cite.styles":"ready","skins.vector.search.codex.styles":"ready","skins.vector.styles":"ready","skins.vector.icons":"ready","jquery.makeCollapsible.styles":"ready","ext.wikimediamessages.styles":"ready","ext.visualEditor.desktopArticleTarget.noscript":"ready","ext.uls.interlanguage":"ready","wikibase.client.init":"ready","ext.wikimediaBadges":"ready"};RLPAGEMODULES=["ext.cite.ux-enhancements","ext.scribunto.logs", "site","mediawiki.page.ready","jquery.makeCollapsible","mediawiki.toc","skins.vector.js","ext.centralNotice.geoIP","ext.centralNotice.startUp","ext.gadget.ReferenceTooltips","ext.gadget.switcher","ext.urlShortener.toolbar","ext.centralauth.centralautologin","mmv.bootstrap","ext.popups","ext.visualEditor.desktopArticleTarget.init","ext.visualEditor.targetLoader","ext.echo.centralauth","ext.eventLogging","ext.wikimediaEvents","ext.navigationTiming","ext.uls.interface","ext.cx.eventlogging.campaigns","ext.cx.uls.quick.actions","wikibase.client.vector-2022","ext.checkUser.clientHints","ext.growthExperiments.SuggestedEditSession","wikibase.sidebar.tracking"];</script> <script>(RLQ=window.RLQ||[]).push(function(){mw.loader.impl(function(){return["user.options@12s5i",function($,jQuery,require,module){mw.user.tokens.set({"patrolToken":"+\\","watchToken":"+\\","csrfToken":"+\\"}); }];});});</script> <link rel="stylesheet" href="/w/load.php?lang=en&modules=ext.cite.styles%7Cext.uls.interlanguage%7Cext.visualEditor.desktopArticleTarget.noscript%7Cext.wikimediaBadges%7Cext.wikimediamessages.styles%7Cjquery.makeCollapsible.styles%7Cskins.vector.icons%2Cstyles%7Cskins.vector.search.codex.styles%7Cwikibase.client.init&only=styles&skin=vector-2022"> <script async="" src="/w/load.php?lang=en&modules=startup&only=scripts&raw=1&skin=vector-2022"></script> <meta name="ResourceLoaderDynamicStyles" content=""> <link rel="stylesheet" href="/w/load.php?lang=en&modules=site.styles&only=styles&skin=vector-2022"> <meta name="generator" content="MediaWiki 1.44.0-wmf.4"> <meta name="referrer" content="origin"> <meta name="referrer" content="origin-when-cross-origin"> <meta name="robots" content="max-image-preview:standard"> <meta name="format-detection" content="telephone=no"> <meta name="viewport" content="width=1120"> <meta property="og:title" content="Hierarchy of evidence - Wikipedia"> <meta property="og:type" content="website"> <link rel="preconnect" href="//upload.wikimedia.org"> <link rel="alternate" media="only screen and (max-width: 640px)" href="//en.m.wikipedia.org/wiki/Hierarchy_of_evidence"> <link rel="alternate" type="application/x-wiki" title="Edit this page" href="/w/index.php?title=Hierarchy_of_evidence&action=edit"> <link rel="apple-touch-icon" href="/static/apple-touch/wikipedia.png"> <link rel="icon" href="/static/favicon/wikipedia.ico"> <link rel="search" type="application/opensearchdescription+xml" href="/w/rest.php/v1/search" title="Wikipedia (en)"> <link rel="EditURI" type="application/rsd+xml" href="//en.wikipedia.org/w/api.php?action=rsd"> <link rel="canonical" href="https://en.wikipedia.org/wiki/Hierarchy_of_evidence"> <link rel="license" href="https://creativecommons.org/licenses/by-sa/4.0/deed.en"> <link rel="alternate" type="application/atom+xml" title="Wikipedia Atom feed" href="/w/index.php?title=Special:RecentChanges&feed=atom"> <link rel="dns-prefetch" href="//meta.wikimedia.org" /> <link rel="dns-prefetch" href="//login.wikimedia.org"> </head> <body class="skin--responsive skin-vector skin-vector-search-vue mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject mw-editable page-Hierarchy_of_evidence rootpage-Hierarchy_of_evidence skin-vector-2022 action-view"><a class="mw-jump-link" href="#bodyContent">Jump to content</a> <div class="vector-header-container"> <header class="vector-header mw-header"> <div class="vector-header-start"> <nav class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-dropdown" class="vector-dropdown vector-main-menu-dropdown vector-button-flush-left vector-button-flush-right" > <input type="checkbox" id="vector-main-menu-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-main-menu-dropdown" class="vector-dropdown-checkbox " aria-label="Main menu" > <label id="vector-main-menu-dropdown-label" for="vector-main-menu-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-menu mw-ui-icon-wikimedia-menu"></span> <span class="vector-dropdown-label-text">Main menu</span> </label> <div class="vector-dropdown-content"> <div id="vector-main-menu-unpinned-container" class="vector-unpinned-container"> <div id="vector-main-menu" class="vector-main-menu vector-pinnable-element"> <div class="vector-pinnable-header vector-main-menu-pinnable-header vector-pinnable-header-unpinned" data-feature-name="main-menu-pinned" data-pinnable-element-id="vector-main-menu" data-pinned-container-id="vector-main-menu-pinned-container" data-unpinned-container-id="vector-main-menu-unpinned-container" > <div class="vector-pinnable-header-label">Main menu</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-main-menu.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-main-menu.unpin">hide</button> </div> <div id="p-navigation" class="vector-menu mw-portlet mw-portlet-navigation" > <div class="vector-menu-heading"> Navigation </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-mainpage-description" class="mw-list-item"><a href="/wiki/Main_Page" title="Visit the main page [z]" accesskey="z"><span>Main page</span></a></li><li id="n-contents" class="mw-list-item"><a href="/wiki/Wikipedia:Contents" title="Guides to browsing Wikipedia"><span>Contents</span></a></li><li id="n-currentevents" class="mw-list-item"><a href="/wiki/Portal:Current_events" title="Articles related to current events"><span>Current events</span></a></li><li id="n-randompage" class="mw-list-item"><a href="/wiki/Special:Random" title="Visit a randomly selected article [x]" accesskey="x"><span>Random article</span></a></li><li id="n-aboutsite" class="mw-list-item"><a href="/wiki/Wikipedia:About" title="Learn about Wikipedia and how it works"><span>About Wikipedia</span></a></li><li id="n-contactpage" class="mw-list-item"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us" title="How to contact Wikipedia"><span>Contact us</span></a></li> </ul> </div> </div> <div id="p-interaction" class="vector-menu mw-portlet mw-portlet-interaction" > <div class="vector-menu-heading"> Contribute </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-help" class="mw-list-item"><a href="/wiki/Help:Contents" title="Guidance on how to use and edit Wikipedia"><span>Help</span></a></li><li id="n-introduction" class="mw-list-item"><a href="/wiki/Help:Introduction" title="Learn how to edit Wikipedia"><span>Learn to edit</span></a></li><li id="n-portal" class="mw-list-item"><a href="/wiki/Wikipedia:Community_portal" title="The hub for editors"><span>Community portal</span></a></li><li id="n-recentchanges" class="mw-list-item"><a href="/wiki/Special:RecentChanges" title="A list of recent changes to Wikipedia [r]" accesskey="r"><span>Recent changes</span></a></li><li id="n-upload" class="mw-list-item"><a href="/wiki/Wikipedia:File_upload_wizard" title="Add images or other media for use on Wikipedia"><span>Upload file</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> <a href="/wiki/Main_Page" class="mw-logo"> <img class="mw-logo-icon" src="/static/images/icons/wikipedia.png" alt="" aria-hidden="true" height="50" width="50"> <span class="mw-logo-container skin-invert"> <img class="mw-logo-wordmark" alt="Wikipedia" src="/static/images/mobile/copyright/wikipedia-wordmark-en.svg" style="width: 7.5em; height: 1.125em;"> <img class="mw-logo-tagline" alt="The Free Encyclopedia" src="/static/images/mobile/copyright/wikipedia-tagline-en.svg" width="117" height="13" style="width: 7.3125em; height: 0.8125em;"> </span> </a> </div> <div class="vector-header-end"> <div id="p-search" role="search" class="vector-search-box-vue vector-search-box-collapses vector-search-box-show-thumbnail vector-search-box-auto-expand-width vector-search-box"> <a href="/wiki/Special:Search" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only search-toggle" title="Search Wikipedia [f]" accesskey="f"><span class="vector-icon mw-ui-icon-search mw-ui-icon-wikimedia-search"></span> <span>Search</span> </a> <div class="vector-typeahead-search-container"> <div class="cdx-typeahead-search cdx-typeahead-search--show-thumbnail cdx-typeahead-search--auto-expand-width"> <form action="/w/index.php" id="searchform" class="cdx-search-input cdx-search-input--has-end-button"> <div id="simpleSearch" class="cdx-search-input__input-wrapper" data-search-loc="header-moved"> <div class="cdx-text-input cdx-text-input--has-start-icon"> <input class="cdx-text-input__input" type="search" name="search" placeholder="Search Wikipedia" aria-label="Search Wikipedia" autocapitalize="sentences" title="Search Wikipedia [f]" accesskey="f" id="searchInput" > <span class="cdx-text-input__icon cdx-text-input__start-icon"></span> </div> <input type="hidden" name="title" value="Special:Search"> </div> <button class="cdx-button cdx-search-input__end-button">Search</button> </form> </div> </div> </div> <nav class="vector-user-links vector-user-links-wide" aria-label="Personal tools"> <div class="vector-user-links-main"> <div id="p-vector-user-menu-preferences" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-userpage" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-dropdown" class="vector-dropdown " title="Change the appearance of the page's font size, width, and color" > <input type="checkbox" id="vector-appearance-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-appearance-dropdown" class="vector-dropdown-checkbox " aria-label="Appearance" > <label id="vector-appearance-dropdown-label" for="vector-appearance-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-appearance mw-ui-icon-wikimedia-appearance"></span> <span class="vector-dropdown-label-text">Appearance</span> </label> <div class="vector-dropdown-content"> <div id="vector-appearance-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <div id="p-vector-user-menu-notifications" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-overflow" class="vector-menu mw-portlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="https://donate.wikimedia.org/wiki/Special:FundraiserRedirector?utm_source=donate&utm_medium=sidebar&utm_campaign=C13_en.wikipedia.org&uselang=en" class=""><span>Donate</span></a> </li> <li id="pt-createaccount-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:CreateAccount&returnto=Hierarchy+of+evidence" title="You are encouraged to create an account and log in; however, it is not mandatory" class=""><span>Create account</span></a> </li> <li id="pt-login-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:UserLogin&returnto=Hierarchy+of+evidence" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o" class=""><span>Log in</span></a> </li> </ul> </div> </div> </div> <div id="vector-user-links-dropdown" class="vector-dropdown vector-user-menu vector-button-flush-right vector-user-menu-logged-out" title="Log in and more options" > <input type="checkbox" id="vector-user-links-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-user-links-dropdown" class="vector-dropdown-checkbox " aria-label="Personal tools" > <label id="vector-user-links-dropdown-label" for="vector-user-links-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-ellipsis mw-ui-icon-wikimedia-ellipsis"></span> <span class="vector-dropdown-label-text">Personal tools</span> </label> <div class="vector-dropdown-content"> <div id="p-personal" class="vector-menu mw-portlet mw-portlet-personal user-links-collapsible-item" title="User menu" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport" class="user-links-collapsible-item mw-list-item"><a href="https://donate.wikimedia.org/wiki/Special:FundraiserRedirector?utm_source=donate&utm_medium=sidebar&utm_campaign=C13_en.wikipedia.org&uselang=en"><span>Donate</span></a></li><li id="pt-createaccount" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:CreateAccount&returnto=Hierarchy+of+evidence" title="You are encouraged to create an account and log in; however, it is not mandatory"><span class="vector-icon mw-ui-icon-userAdd mw-ui-icon-wikimedia-userAdd"></span> <span>Create account</span></a></li><li id="pt-login" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:UserLogin&returnto=Hierarchy+of+evidence" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o"><span class="vector-icon mw-ui-icon-logIn mw-ui-icon-wikimedia-logIn"></span> <span>Log in</span></a></li> </ul> </div> </div> <div id="p-user-menu-anon-editor" class="vector-menu mw-portlet mw-portlet-user-menu-anon-editor" > <div class="vector-menu-heading"> Pages for logged out editors <a href="/wiki/Help:Introduction" aria-label="Learn more about editing"><span>learn more</span></a> </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-anoncontribs" class="mw-list-item"><a href="/wiki/Special:MyContributions" title="A list of edits made from this IP address [y]" accesskey="y"><span>Contributions</span></a></li><li id="pt-anontalk" class="mw-list-item"><a href="/wiki/Special:MyTalk" title="Discussion about edits from this IP address [n]" accesskey="n"><span>Talk</span></a></li> </ul> </div> </div> </div> </div> </nav> </div> </header> </div> <div class="mw-page-container"> <div class="mw-page-container-inner"> <div class="vector-sitenotice-container"> <div id="siteNotice"></div> </div> <div class="vector-column-start"> <div class="vector-main-menu-container"> <div id="mw-navigation"> <nav id="mw-panel" class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-pinned-container" class="vector-pinned-container"> </div> </nav> </div> </div> <div class="vector-sticky-pinned-container"> <nav id="mw-panel-toc" aria-label="Contents" data-event-name="ui.sidebar-toc" class="mw-table-of-contents-container vector-toc-landmark"> <div id="vector-toc-pinned-container" class="vector-pinned-container"> <div id="vector-toc" class="vector-toc vector-pinnable-element"> <div class="vector-pinnable-header vector-toc-pinnable-header vector-pinnable-header-pinned" data-feature-name="toc-pinned" data-pinnable-element-id="vector-toc" > <h2 class="vector-pinnable-header-label">Contents</h2> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-toc.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-toc.unpin">hide</button> </div> <ul class="vector-toc-contents" id="mw-panel-toc-list"> <li id="toc-mw-content-text" class="vector-toc-list-item vector-toc-level-1"> <a href="#" class="vector-toc-link"> <div class="vector-toc-text">(Top)</div> </a> </li> <li id="toc-Definition" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Definition"> <div class="vector-toc-text"> <span class="vector-toc-numb">1</span> <span>Definition</span> </div> </a> <ul id="toc-Definition-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Examples" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Examples"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>Examples</span> </div> </a> <button aria-controls="toc-Examples-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Examples subsection</span> </button> <ul id="toc-Examples-sublist" class="vector-toc-list"> <li id="toc-GRADE" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#GRADE"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.1</span> <span>GRADE</span> </div> </a> <ul id="toc-GRADE-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Guyatt_and_Sackett" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Guyatt_and_Sackett"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.2</span> <span>Guyatt and Sackett</span> </div> </a> <ul id="toc-Guyatt_and_Sackett-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Saunders_et_al." class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Saunders_et_al."> <div class="vector-toc-text"> <span class="vector-toc-numb">2.3</span> <span>Saunders et al.</span> </div> </a> <ul id="toc-Saunders_et_al.-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Khan_et_al." class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Khan_et_al."> <div class="vector-toc-text"> <span class="vector-toc-numb">2.4</span> <span>Khan et al.</span> </div> </a> <ul id="toc-Khan_et_al.-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-U.S._National_Registry_of_Evidence-Based_Practices_and_Programs" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#U.S._National_Registry_of_Evidence-Based_Practices_and_Programs"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.5</span> <span>U.S. National Registry of Evidence-Based Practices and Programs</span> </div> </a> <ul id="toc-U.S._National_Registry_of_Evidence-Based_Practices_and_Programs-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-History" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#History"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>History</span> </div> </a> <button aria-controls="toc-History-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle History subsection</span> </button> <ul id="toc-History-sublist" class="vector-toc-list"> <li id="toc-Canada" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Canada"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.1</span> <span>Canada</span> </div> </a> <ul id="toc-Canada-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-United_States" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#United_States"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.2</span> <span>United States</span> </div> </a> <ul id="toc-United_States-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-United_Kingdom" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#United_Kingdom"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.3</span> <span>United Kingdom</span> </div> </a> <ul id="toc-United_Kingdom-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Global" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Global"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.4</span> <span>Global</span> </div> </a> <ul id="toc-Global-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Proponents" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Proponents"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Proponents</span> </div> </a> <ul id="toc-Proponents-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Criticism" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Criticism"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>Criticism</span> </div> </a> <ul id="toc-Criticism-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>See also</span> </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>References</span> </div> </a> <button aria-controls="toc-References-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle References subsection</span> </button> <ul id="toc-References-sublist" class="vector-toc-list"> <li id="toc-Works_cited" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Works_cited"> <div class="vector-toc-text"> <span class="vector-toc-numb">7.1</span> <span>Works cited</span> </div> </a> <ul id="toc-Works_cited-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-External_links" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#External_links"> <div class="vector-toc-text"> <span class="vector-toc-numb">8</span> <span>External links</span> </div> </a> <ul id="toc-External_links-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Toggle the table of contents</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-titlebar-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <h1 id="firstHeading" class="firstHeading mw-first-heading"><span class="mw-page-title-main">Hierarchy of evidence</span></h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Go to an article in another language. Available in 5 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-5" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">5 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D8%AA%D8%B1%D8%A7%D8%AA%D8%A8%D9%8A%D8%A9_%D8%A7%D9%84%D8%AF%D9%84%D9%8A%D9%84" title="تراتبية الدليل – Arabic" lang="ar" hreflang="ar" data-title="تراتبية الدليل" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%98%D0%B5%D1%80%D0%B0%D1%80%D1%85%D0%B8%D1%8F_%D0%B4%D0%BE%D0%BA%D0%B0%D0%B7%D0%B0%D1%82%D0%B5%D0%BB%D1%8C%D1%81%D1%82%D0%B2" title="Иерархия доказательств – Russian" lang="ru" hreflang="ru" data-title="Иерархия доказательств" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/Evidenshierarki" title="Evidenshierarki – Swedish" lang="sv" hreflang="sv" data-title="Evidenshierarki" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-th mw-list-item"><a href="https://th.wikipedia.org/wiki/%E0%B8%A5%E0%B8%B3%E0%B8%94%E0%B8%B1%E0%B8%9A%E0%B8%8A%E0%B8%B1%E0%B9%89%E0%B8%99%E0%B8%AB%E0%B8%A5%E0%B8%B1%E0%B8%81%E0%B8%90%E0%B8%B2%E0%B8%99" title="ลำดับชั้นหลักฐาน – Thai" lang="th" hreflang="th" data-title="ลำดับชั้นหลักฐาน" data-language-autonym="ไทย" data-language-local-name="Thai" class="interlanguage-link-target"><span>ไทย</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E8%AD%89%E6%93%9A%E7%AD%89%E7%B4%9A" title="證據等級 – Chinese" lang="zh" hreflang="zh" data-title="證據等級" data-language-autonym="中文" data-language-local-name="Chinese" class="interlanguage-link-target"><span>中文</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q17135794#sitelinks-wikipedia" title="Edit interlanguage links" class="wbc-editpage">Edit links</a></span></div> </div> </div> </div> </header> <div class="vector-page-toolbar"> <div class="vector-page-toolbar-container"> <div id="left-navigation"> <nav aria-label="Namespaces"> <div id="p-associated-pages" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-associated-pages" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-nstab-main" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/Hierarchy_of_evidence" title="View the content page [c]" accesskey="c"><span>Article</span></a></li><li id="ca-talk" class="vector-tab-noicon mw-list-item"><a href="/wiki/Talk:Hierarchy_of_evidence" rel="discussion" title="Discuss improvements to the content page [t]" accesskey="t"><span>Talk</span></a></li> </ul> </div> </div> <div id="vector-variants-dropdown" class="vector-dropdown emptyPortlet" > <input type="checkbox" id="vector-variants-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-variants-dropdown" class="vector-dropdown-checkbox " aria-label="Change language variant" > <label id="vector-variants-dropdown-label" for="vector-variants-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" ><span class="vector-dropdown-label-text">English</span> </label> <div class="vector-dropdown-content"> <div id="p-variants" class="vector-menu mw-portlet mw-portlet-variants emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> </div> </div> </nav> </div> <div id="right-navigation" class="vector-collapsible"> <nav aria-label="Views"> <div id="p-views" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-views" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-view" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/Hierarchy_of_evidence"><span>Read</span></a></li><li id="ca-edit" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Hierarchy_of_evidence&action=edit" title="Edit this page [e]" accesskey="e"><span>Edit</span></a></li><li id="ca-history" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Hierarchy_of_evidence&action=history" title="Past revisions of this page [h]" accesskey="h"><span>View history</span></a></li> </ul> </div> </div> </nav> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-dropdown" class="vector-dropdown vector-page-tools-dropdown" > <input type="checkbox" id="vector-page-tools-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-tools-dropdown" class="vector-dropdown-checkbox " aria-label="Tools" > <label id="vector-page-tools-dropdown-label" for="vector-page-tools-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" ><span class="vector-dropdown-label-text">Tools</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-tools-unpinned-container" class="vector-unpinned-container"> <div id="vector-page-tools" class="vector-page-tools vector-pinnable-element"> <div class="vector-pinnable-header vector-page-tools-pinnable-header vector-pinnable-header-unpinned" data-feature-name="page-tools-pinned" data-pinnable-element-id="vector-page-tools" data-pinned-container-id="vector-page-tools-pinned-container" data-unpinned-container-id="vector-page-tools-unpinned-container" > <div class="vector-pinnable-header-label">Tools</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-page-tools.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-page-tools.unpin">hide</button> </div> <div id="p-cactions" class="vector-menu mw-portlet mw-portlet-cactions emptyPortlet vector-has-collapsible-items" title="More options" > <div class="vector-menu-heading"> Actions </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-more-view" class="selected vector-more-collapsible-item mw-list-item"><a href="/wiki/Hierarchy_of_evidence"><span>Read</span></a></li><li id="ca-more-edit" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Hierarchy_of_evidence&action=edit" title="Edit this page [e]" accesskey="e"><span>Edit</span></a></li><li id="ca-more-history" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Hierarchy_of_evidence&action=history"><span>View history</span></a></li> </ul> </div> </div> <div id="p-tb" class="vector-menu mw-portlet mw-portlet-tb" > <div class="vector-menu-heading"> General </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="t-whatlinkshere" class="mw-list-item"><a href="/wiki/Special:WhatLinksHere/Hierarchy_of_evidence" title="List of all English Wikipedia pages containing links to this page [j]" accesskey="j"><span>What links here</span></a></li><li id="t-recentchangeslinked" class="mw-list-item"><a href="/wiki/Special:RecentChangesLinked/Hierarchy_of_evidence" rel="nofollow" title="Recent changes in pages linked from this page [k]" accesskey="k"><span>Related changes</span></a></li><li id="t-upload" class="mw-list-item"><a href="/wiki/Wikipedia:File_Upload_Wizard" title="Upload files [u]" accesskey="u"><span>Upload file</span></a></li><li id="t-specialpages" class="mw-list-item"><a href="/wiki/Special:SpecialPages" title="A list of all special pages [q]" accesskey="q"><span>Special pages</span></a></li><li id="t-permalink" class="mw-list-item"><a href="/w/index.php?title=Hierarchy_of_evidence&oldid=1243995306" title="Permanent link to this revision of this page"><span>Permanent link</span></a></li><li id="t-info" class="mw-list-item"><a href="/w/index.php?title=Hierarchy_of_evidence&action=info" title="More information about this page"><span>Page information</span></a></li><li id="t-cite" class="mw-list-item"><a href="/w/index.php?title=Special:CiteThisPage&page=Hierarchy_of_evidence&id=1243995306&wpFormIdentifier=titleform" title="Information on how to cite this page"><span>Cite this page</span></a></li><li id="t-urlshortener" class="mw-list-item"><a href="/w/index.php?title=Special:UrlShortener&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FHierarchy_of_evidence"><span>Get shortened URL</span></a></li><li id="t-urlshortener-qrcode" class="mw-list-item"><a href="/w/index.php?title=Special:QrCode&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FHierarchy_of_evidence"><span>Download QR code</span></a></li> </ul> </div> </div> <div id="p-coll-print_export" class="vector-menu mw-portlet mw-portlet-coll-print_export" > <div class="vector-menu-heading"> Print/export </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="coll-download-as-rl" class="mw-list-item"><a href="/w/index.php?title=Special:DownloadAsPdf&page=Hierarchy_of_evidence&action=show-download-screen" title="Download this page as a PDF file"><span>Download as PDF</span></a></li><li id="t-print" class="mw-list-item"><a href="/w/index.php?title=Hierarchy_of_evidence&printable=yes" title="Printable version of this page [p]" accesskey="p"><span>Printable version</span></a></li> </ul> </div> </div> <div id="p-wikibase-otherprojects" class="vector-menu mw-portlet mw-portlet-wikibase-otherprojects" > <div class="vector-menu-heading"> In other projects </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="wb-otherproject-link wb-otherproject-commons mw-list-item"><a href="https://commons.wikimedia.org/wiki/Category:Hierarchy_of_evidence" hreflang="en"><span>Wikimedia Commons</span></a></li><li id="t-wikibase" class="wb-otherproject-link wb-otherproject-wikibase-dataitem mw-list-item"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q17135794" title="Structured data on this page hosted by Wikidata [g]" accesskey="g"><span>Wikidata item</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> </div> </div> </div> <div class="vector-column-end"> <div class="vector-sticky-pinned-container"> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-pinned-container" class="vector-pinned-container"> </div> </nav> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-pinned-container" class="vector-pinned-container"> <div id="vector-appearance" class="vector-appearance vector-pinnable-element"> <div class="vector-pinnable-header vector-appearance-pinnable-header vector-pinnable-header-pinned" data-feature-name="appearance-pinned" data-pinnable-element-id="vector-appearance" data-pinned-container-id="vector-appearance-pinned-container" data-unpinned-container-id="vector-appearance-unpinned-container" > <div class="vector-pinnable-header-label">Appearance</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-appearance.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-appearance.unpin">hide</button> </div> </div> </div> </nav> </div> </div> <div id="bodyContent" class="vector-body" aria-labelledby="firstHeading" data-mw-ve-target-container> <div class="vector-body-before-content"> <div class="mw-indicators"> </div> <div id="siteSub" class="noprint">From Wikipedia, the free encyclopedia</div> </div> <div id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Heuristic ranking science research results</div> <style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist dl dl,.mw-parser-output .hlist dl ol,.mw-parser-output .hlist dl ul,.mw-parser-output .hlist ol dl,.mw-parser-output .hlist ol ol,.mw-parser-output .hlist ol ul,.mw-parser-output .hlist ul dl,.mw-parser-output .hlist ul ol,.mw-parser-output .hlist ul ul{display:inline}.mw-parser-output .hlist .mw-empty-li{display:none}.mw-parser-output .hlist dt::after{content:": "}.mw-parser-output .hlist dd::after,.mw-parser-output .hlist li::after{content:" · ";font-weight:bold}.mw-parser-output .hlist dd:last-child::after,.mw-parser-output .hlist dt:last-child::after,.mw-parser-output .hlist li:last-child::after{content:none}.mw-parser-output .hlist dd dd:first-child::before,.mw-parser-output .hlist dd dt:first-child::before,.mw-parser-output .hlist dd li:first-child::before,.mw-parser-output .hlist dt dd:first-child::before,.mw-parser-output .hlist dt dt:first-child::before,.mw-parser-output .hlist dt li:first-child::before,.mw-parser-output .hlist li dd:first-child::before,.mw-parser-output .hlist li dt:first-child::before,.mw-parser-output .hlist li li:first-child::before{content:" (";font-weight:normal}.mw-parser-output .hlist dd dd:last-child::after,.mw-parser-output .hlist dd dt:last-child::after,.mw-parser-output .hlist dd li:last-child::after,.mw-parser-output .hlist dt dd:last-child::after,.mw-parser-output .hlist dt dt:last-child::after,.mw-parser-output .hlist dt li:last-child::after,.mw-parser-output .hlist li dd:last-child::after,.mw-parser-output .hlist li dt:last-child::after,.mw-parser-output .hlist li li:last-child::after{content:")";font-weight:normal}.mw-parser-output .hlist ol{counter-reset:listitem}.mw-parser-output .hlist ol>li{counter-increment:listitem}.mw-parser-output .hlist ol>li::before{content:" "counter(listitem)"\a0 "}.mw-parser-output .hlist dd ol>li:first-child::before,.mw-parser-output .hlist dt ol>li:first-child::before,.mw-parser-output .hlist li ol>li:first-child::before{content:" ("counter(listitem)"\a0 "}</style><style data-mw-deduplicate="TemplateStyles:r1246091330">.mw-parser-output .sidebar{width:22em;float:right;clear:right;margin:0.5em 0 1em 1em;background:var(--background-color-neutral-subtle,#f8f9fa);border:1px solid var(--border-color-base,#a2a9b1);padding:0.2em;text-align:center;line-height:1.4em;font-size:88%;border-collapse:collapse;display:table}body.skin-minerva .mw-parser-output .sidebar{display:table!important;float:right!important;margin:0.5em 0 1em 1em!important}.mw-parser-output .sidebar-subgroup{width:100%;margin:0;border-spacing:0}.mw-parser-output .sidebar-left{float:left;clear:left;margin:0.5em 1em 1em 0}.mw-parser-output .sidebar-none{float:none;clear:both;margin:0.5em 1em 1em 0}.mw-parser-output .sidebar-outer-title{padding:0 0.4em 0.2em;font-size:125%;line-height:1.2em;font-weight:bold}.mw-parser-output .sidebar-top-image{padding:0.4em}.mw-parser-output .sidebar-top-caption,.mw-parser-output .sidebar-pretitle-with-top-image,.mw-parser-output .sidebar-caption{padding:0.2em 0.4em 0;line-height:1.2em}.mw-parser-output .sidebar-pretitle{padding:0.4em 0.4em 0;line-height:1.2em}.mw-parser-output .sidebar-title,.mw-parser-output .sidebar-title-with-pretitle{padding:0.2em 0.8em;font-size:145%;line-height:1.2em}.mw-parser-output .sidebar-title-with-pretitle{padding:0.1em 0.4em}.mw-parser-output .sidebar-image{padding:0.2em 0.4em 0.4em}.mw-parser-output .sidebar-heading{padding:0.1em 0.4em}.mw-parser-output .sidebar-content{padding:0 0.5em 0.4em}.mw-parser-output .sidebar-content-with-subgroup{padding:0.1em 0.4em 0.2em}.mw-parser-output .sidebar-above,.mw-parser-output .sidebar-below{padding:0.3em 0.8em;font-weight:bold}.mw-parser-output .sidebar-collapse .sidebar-above,.mw-parser-output .sidebar-collapse .sidebar-below{border-top:1px solid #aaa;border-bottom:1px solid #aaa}.mw-parser-output .sidebar-navbar{text-align:right;font-size:115%;padding:0 0.4em 0.4em}.mw-parser-output .sidebar-list-title{padding:0 0.4em;text-align:left;font-weight:bold;line-height:1.6em;font-size:105%}.mw-parser-output .sidebar-list-title-c{padding:0 0.4em;text-align:center;margin:0 3.3em}@media(max-width:640px){body.mediawiki .mw-parser-output .sidebar{width:100%!important;clear:both;float:none!important;margin-left:0!important;margin-right:0!important}}body.skin--responsive .mw-parser-output .sidebar a>img{max-width:none!important}@media screen{html.skin-theme-clientpref-night .mw-parser-output .sidebar:not(.notheme) .sidebar-list-title,html.skin-theme-clientpref-night .mw-parser-output .sidebar:not(.notheme) .sidebar-title-with-pretitle{background:transparent!important}html.skin-theme-clientpref-night .mw-parser-output .sidebar:not(.notheme) .sidebar-title-with-pretitle a{color:var(--color-progressive)!important}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .sidebar:not(.notheme) .sidebar-list-title,html.skin-theme-clientpref-os .mw-parser-output .sidebar:not(.notheme) .sidebar-title-with-pretitle{background:transparent!important}html.skin-theme-clientpref-os .mw-parser-output .sidebar:not(.notheme) .sidebar-title-with-pretitle a{color:var(--color-progressive)!important}}@media print{body.ns-0 .mw-parser-output .sidebar{display:none!important}}</style><table class="sidebar nomobile nowraplinks"><tbody><tr><td class="sidebar-pretitle">Part of <a href="/wiki/Category:Evidence-based_practices" title="Category:Evidence-based practices">a series</a> on</td></tr><tr><th class="sidebar-title-with-pretitle"><a href="/wiki/Evidence-based_practice" title="Evidence-based practice">Evidence-based practices</a></th></tr><tr><td class="sidebar-content hlist"> <ul><li><a href="/wiki/Evidence-based_assessment" title="Evidence-based assessment">Assessment</a></li> <li><a href="/wiki/Evidence-based_design" title="Evidence-based design">Design</a></li> <li><a href="/wiki/Evidence-based_management" title="Evidence-based management">Management</a></li> <li><a href="/wiki/Metascience" title="Metascience">Research</a></li> <li><a href="/wiki/Evidence-based_scheduling" title="Evidence-based scheduling">Scheduling</a></li></ul> <hr /> <ul><li><a href="/wiki/Evidence-based_dentistry" title="Evidence-based dentistry">Dentistry</a></li> <li><a href="/wiki/Evidence-based_medical_ethics" title="Evidence-based medical ethics">Medical ethics</a></li> <li><a href="/wiki/Evidence-based_medicine" title="Evidence-based medicine">Medicine</a></li> <li><a href="/wiki/Evidence-based_nursing" title="Evidence-based nursing">Nursing</a></li> <li><a href="/wiki/Evidence-based_pharmacy_in_developing_countries" title="Evidence-based pharmacy in developing countries">Pharmacy</a></li> <li><a href="/wiki/Evidence-based_toxicology" title="Evidence-based toxicology">Toxicology</a></li></ul> <hr /> <ul><li><a href="/wiki/Evidence-based_conservation" title="Evidence-based conservation">Conservation</a></li> <li><a href="/wiki/Evidence-based_education" title="Evidence-based education">Education</a></li> <li><a href="/wiki/Evidence-based_legislation" title="Evidence-based legislation">Legislation</a></li> <li><a href="/wiki/Evidence-based_library_and_information_practice" title="Evidence-based library and information practice">Library and information practice</a></li> <li><a href="/wiki/Evidence-based_policy" title="Evidence-based policy">Policy</a></li> <li><a href="/wiki/Evidence-based_policing" title="Evidence-based policing">Policing</a></li> <li><a href="/wiki/Evidence-based_prosecution" title="Evidence-based prosecution">Prosecution</a></li></ul></td> </tr><tr><td class="sidebar-navbar"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><style data-mw-deduplicate="TemplateStyles:r1239400231">.mw-parser-output .navbar{display:inline;font-size:88%;font-weight:normal}.mw-parser-output .navbar-collapse{float:left;text-align:left}.mw-parser-output .navbar-boxtext{word-spacing:0}.mw-parser-output .navbar ul{display:inline-block;white-space:nowrap;line-height:inherit}.mw-parser-output .navbar-brackets::before{margin-right:-0.125em;content:"[ "}.mw-parser-output .navbar-brackets::after{margin-left:-0.125em;content:" ]"}.mw-parser-output .navbar li{word-spacing:-0.125em}.mw-parser-output .navbar a>span,.mw-parser-output .navbar a>abbr{text-decoration:inherit}.mw-parser-output .navbar-mini abbr{font-variant:small-caps;border-bottom:none;text-decoration:none;cursor:inherit}.mw-parser-output .navbar-ct-full{font-size:114%;margin:0 7em}.mw-parser-output .navbar-ct-mini{font-size:114%;margin:0 4em}html.skin-theme-clientpref-night .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}@media(prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}}@media print{.mw-parser-output .navbar{display:none!important}}</style><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Evidence-based_practices" title="Template:Evidence-based practices"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Evidence-based_practices" title="Template talk:Evidence-based practices"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Evidence-based_practices" title="Special:EditPage/Template:Evidence-based practices"><abbr title="Edit this template">e</abbr></a></li></ul></div></td></tr></tbody></table> <p>A <b>hierarchy of evidence</b>, comprising <b>levels of evidence</b> (<b>LOEs</b>), that is, <b>evidence levels</b> (<b>ELs</b>), is a <a href="/wiki/Heuristic" title="Heuristic">heuristic</a> used to <a href="/wiki/Ranking" title="Ranking">rank</a> the relative strength of results obtained from <a href="/wiki/Experiment" title="Experiment">experimental</a> research, especially <a href="/wiki/Medical_research" title="Medical research">medical research</a>. There is broad agreement on the relative strength of large-scale, <a href="/wiki/Epidemiology" title="Epidemiology">epidemiological studies</a>. More than 80 different hierarchies have been proposed for assessing medical <a href="/wiki/Evidence" title="Evidence">evidence</a>.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> The design of the study (such as a <a href="/wiki/Case_report" title="Case report">case report</a> for an individual patient or a <a href="/wiki/Blinded_experiment" title="Blinded experiment">blinded</a> <a href="/wiki/Randomized_controlled_trial" title="Randomized controlled trial">randomized controlled trial</a>) and the endpoints measured (such as survival or <a href="/wiki/Quality_of_life" title="Quality of life">quality of life</a>) affect the strength of the evidence. In <a href="/wiki/Clinical_research" title="Clinical research">clinical research</a>, the best evidence for treatment efficacy is mainly from <a href="/wiki/Meta-analysis" title="Meta-analysis">meta-analyses</a> of <a href="/wiki/Randomized_controlled_trial" title="Randomized controlled trial">randomized controlled trials</a> (RCTs).<sup id="cite_ref-Shafee_2-0" class="reference"><a href="#cite_note-Shafee-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> <a href="/wiki/Systematic_review" title="Systematic review">Systematic reviews</a> of completed, high-quality randomized controlled trials – such as those published by the <a href="/wiki/Cochrane_(organisation)" title="Cochrane (organisation)">Cochrane Collaboration</a> – rank the same as systematic review of completed high-quality observational studies in regard to the study of side effects.<sup id="cite_ref-Golder_Loke_Bland_2011_p=e1001026_4-0" class="reference"><a href="#cite_note-Golder_Loke_Bland_2011_p=e1001026-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> Evidence hierarchies are often applied in <a href="/wiki/Evidence-based_practice" title="Evidence-based practice">evidence-based practices</a> and are integral to <a href="/wiki/Evidence-based_medicine" title="Evidence-based medicine">evidence-based medicine</a> (EBM). </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Definition">Definition</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hierarchy_of_evidence&action=edit&section=1" title="Edit section: Definition"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In 2014, Jacob Stegenga defined a hierarchy of evidence as "rank-ordering of kinds of methods according to the potential for that method to suffer from systematic bias". At the top of the hierarchy is a method with the most freedom from systemic bias or best internal validity relative to the tested medical intervention's hypothesized efficacy.<sup id="cite_ref-Stegenga_5-0" class="reference"><a href="#cite_note-Stegenga-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Page / location: 313">: 313 </span></sup> In 1997, Greenhalgh suggested it was "the relative weight carried by the different types of primary study when making decisions about clinical interventions".<sup id="cite_ref-green_6-0" class="reference"><a href="#cite_note-green-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> </p><p>The <a href="/wiki/National_Cancer_Institute" title="National Cancer Institute">National Cancer Institute</a> defines levels of evidence as "a <a href="/wiki/Ranking_system" class="mw-redirect" title="Ranking system">ranking system</a> used to describe the strength of the results measured in a <a href="/wiki/Clinical_trial" title="Clinical trial">clinical trial</a> or research study. The <a href="/wiki/Study_design" class="mw-redirect" title="Study design">design of the study</a> ... and the endpoints measured ... affect the strength of the evidence."<sup id="cite_ref-nci_7-0" class="reference"><a href="#cite_note-nci-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Examples">Examples</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hierarchy_of_evidence&action=edit&section=2" title="Edit section: Examples"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1237032888/mw-parser-output/.tmulti">.mw-parser-output .tmulti .multiimageinner{display:flex;flex-direction:column}.mw-parser-output .tmulti .trow{display:flex;flex-direction:row;clear:left;flex-wrap:wrap;width:100%;box-sizing:border-box}.mw-parser-output .tmulti .tsingle{margin:1px;float:left}.mw-parser-output .tmulti .theader{clear:both;font-weight:bold;text-align:center;align-self:center;background-color:transparent;width:100%}.mw-parser-output .tmulti .thumbcaption{background-color:transparent}.mw-parser-output .tmulti .text-align-left{text-align:left}.mw-parser-output .tmulti .text-align-right{text-align:right}.mw-parser-output .tmulti .text-align-center{text-align:center}@media all and (max-width:720px){.mw-parser-output .tmulti .thumbinner{width:100%!important;box-sizing:border-box;max-width:none!important;align-items:center}.mw-parser-output .tmulti .trow{justify-content:center}.mw-parser-output .tmulti .tsingle{float:none!important;max-width:100%!important;box-sizing:border-box;text-align:center}.mw-parser-output .tmulti .tsingle .thumbcaption{text-align:left}.mw-parser-output .tmulti .trow>.thumbcaption{text-align:center}}@media screen{html.skin-theme-clientpref-night .mw-parser-output .tmulti .multiimageinner img{background-color:white}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .tmulti .multiimageinner img{background-color:white}}</style><div class="thumb tmulti tright"><div class="thumbinner multiimageinner" style="width:304px;max-width:304px"><div class="trow"><div class="tsingle" style="width:302px;max-width:302px"><div class="thumbimage"><span typeof="mw:File"><a href="/wiki/File:Research_design_and_evidence.svg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/3/36/Research_design_and_evidence.svg/300px-Research_design_and_evidence.svg.png" decoding="async" width="300" height="225" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/3/36/Research_design_and_evidence.svg/450px-Research_design_and_evidence.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/3/36/Research_design_and_evidence.svg/600px-Research_design_and_evidence.svg.png 2x" data-file-width="707" data-file-height="530" /></a></span></div><div class="thumbcaption"><a href="/wiki/Procter_%26_Gamble" title="Procter & Gamble">Procter & Gamble</a><sup id="cite_ref-dentalcare.com_8-0" class="reference"><a href="#cite_note-dentalcare.com-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup></div></div></div><div class="trow"><div class="tsingle" style="width:302px;max-width:302px"><div class="thumbimage"><span typeof="mw:File"><a href="/wiki/File:Research_design_and_evidence_-_Capho.svg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/d/dc/Research_design_and_evidence_-_Capho.svg/300px-Research_design_and_evidence_-_Capho.svg.png" decoding="async" width="300" height="225" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/d/dc/Research_design_and_evidence_-_Capho.svg/450px-Research_design_and_evidence_-_Capho.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/d/dc/Research_design_and_evidence_-_Capho.svg/600px-Research_design_and_evidence_-_Capho.svg.png 2x" data-file-width="512" data-file-height="384" /></a></span></div><div class="thumbcaption">Canadian Association of Pharmacy in Oncology<sup id="cite_ref-Capho_9-0" class="reference"><a href="#cite_note-Capho-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup></div></div></div><div class="trow" style="display:flex"><div class="thumbcaption">Example hierarchies of evidence in medicine</div></div></div></div> <p>A large number of hierarchies of evidence have been proposed. Similar protocols for evaluation of research quality are still in development. So far, the available protocols pay relatively little attention to whether outcome research is relevant to efficacy (the outcome of a treatment performed under ideal conditions) or to effectiveness (the outcome of the treatment performed under ordinary, expectable conditions).<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (November 2023)">citation needed</span></a></i>]</sup> </p> <div class="mw-heading mw-heading3"><h3 id="GRADE">GRADE</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hierarchy_of_evidence&action=edit&section=3" title="Edit section: GRADE"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/The_Grading_of_Recommendations_Assessment,_Development_and_Evaluation_(GRADE)_approach" class="mw-redirect" title="The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach">The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach</a></div> <p>The GRADE approach (Grading of Recommendations Assessment, Development and Evaluation) is a method of assessing the certainty in evidence (also known as quality of evidence or confidence in effect estimates) and the strength of recommendations.<sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> The GRADE began in the year 2000 as a collaboration of methodologists, guideline developers, biostatisticians, clinicians, public health scientists and other interested members.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (November 2023)">citation needed</span></a></i>]</sup> </p><p>Over 100 organizations (including the <a href="/wiki/World_Health_Organization" title="World Health Organization">World Health Organization</a>, the UK National Institute for Health and Care Excellence (NICE), the Canadian Task Force for Preventive Health Care, the Colombian Ministry of Health, among others) have endorsed and/or are using GRADE to evaluate the quality of evidence and strength of health care recommendations. (See examples of clinical practice guidelines using GRADE online).<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup> </p><p>GRADES rates quality of evidence as follows:<sup id="cite_ref-grade3_13-0" class="reference"><a href="#cite_note-grade3-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup> </p> <table class="wikitable"> <tbody><tr> <td>High</td> <td>There is a lot of confidence that the true effect lies close to that of the estimated effect. </td></tr> <tr> <td>Moderate</td> <td>There is moderate confidence in the estimated effect: The true effect is likely to be close to the estimated effect, but there is a possibility that it is substantially different. </td></tr> <tr> <td>Low</td> <td>There is limited confidence in the estimated effect: The true effect might be substantially different from the estimated effect. </td></tr> <tr> <td>Very low</td> <td>There is very little confidence in the estimated effect: The true effect is likely to be substantially different from the estimated effect. </td></tr></tbody></table> <div class="mw-heading mw-heading3"><h3 id="Guyatt_and_Sackett">Guyatt and Sackett</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hierarchy_of_evidence&action=edit&section=4" title="Edit section: Guyatt and Sackett"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In 1995, Guyatt and Sackett published the first such hierarchy.<sup id="cite_ref-15" class="reference"><a href="#cite_note-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> </p><p>Greenhalgh put the different types of primary study in the following order:<sup id="cite_ref-green_6-1" class="reference"><a href="#cite_note-green-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> </p> <ol><li><a href="/wiki/Systematic_review" title="Systematic review">Systematic reviews</a> and <a href="/wiki/Meta-analyses" class="mw-redirect" title="Meta-analyses">meta-analyses</a> of "RCTs with definitive results".</li> <li>RCTs with definitive results (confidence intervals that do not overlap the threshold clinically significant effect)</li> <li>RCTs with non-definitive results (a point estimate that suggests a clinically significant effect but with confidence intervals overlapping the threshold for this effect)</li> <li><a href="/wiki/Cohort_studies" class="mw-redirect" title="Cohort studies">Cohort studies</a></li> <li><a href="/wiki/Case%E2%80%93control_studies" class="mw-redirect" title="Case–control studies">Case–control studies</a></li> <li><a href="/wiki/Cross-sectional_study" title="Cross-sectional study">Cross-sectional surveys</a></li> <li><a href="/wiki/Case_reports" class="mw-redirect" title="Case reports">Case reports</a></li></ol> <div class="mw-heading mw-heading3"><h3 id="Saunders_et_al.">Saunders et al.</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hierarchy_of_evidence&action=edit&section=5" title="Edit section: Saunders et al."><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>A protocol suggested by Saunders et al. assigns research reports to six categories, on the basis of research design, theoretical background, evidence of possible harm, and general acceptance. To be classified under this protocol, there must be descriptive publications, including a manual or similar description of the intervention. This protocol does not consider the nature of any comparison group, the effect of confounding variables, the nature of the statistical analysis, or a number of other criteria. Interventions are assessed as belonging to Category 1, well-supported, efficacious treatments, if there are two or more randomized controlled outcome studies comparing the target treatment to an appropriate alternative treatment and showing a significant advantage to the target treatment. Interventions are assigned to Category 2, supported and probably efficacious treatment, based on positive outcomes of nonrandomized designs with some form of control, which may involve a non-treatment group. Category 3, supported and acceptable treatment, includes interventions supported by one controlled or uncontrolled study, or by a series of single-subject studies, or by work with a different population than the one of interest. Category 4, promising and acceptable treatment, includes interventions that have no support except general acceptance and clinical anecdotal literature; however, any evidence of possible harm excludes treatments from this category. Category 5, innovative and novel treatment, includes interventions that are not thought to be harmful, but are not widely used or discussed in the literature. Category 6, concerning treatment, is the classification for treatments that have the possibility of doing harm, as well as having unknown or inappropriate theoretical foundations.<sup id="cite_ref-16" class="reference"><a href="#cite_note-16"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Khan_et_al.">Khan et al.</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hierarchy_of_evidence&action=edit&section=6" title="Edit section: Khan et al."><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>A protocol for evaluation of research quality was suggested by a report from the Centre for Reviews and Dissemination, prepared by Khan et al. and intended as a general method for assessing both medical and psychosocial interventions. While strongly encouraging the use of randomized designs, this protocol noted that such designs were useful only if they met demanding criteria, such as true randomization and concealment of the assigned treatment group from the client and from others, including the individuals assessing the outcome. The Khan et al. protocol emphasized the need to make comparisons on the basis of "intention to treat" in order to avoid problems related to greater attrition in one group. The Khan et al. protocol also presented demanding criteria for nonrandomized studies, including matching of groups on potential confounding variables and adequate descriptions of groups and treatments at every stage, and concealment of treatment choice from persons assessing the outcomes. This protocol did not provide a classification of levels of evidence, but included or excluded treatments from classification as evidence-based depending on whether the research met the stated standards.<sup id="cite_ref-17" class="reference"><a href="#cite_note-17"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="U.S._National_Registry_of_Evidence-Based_Practices_and_Programs">U.S. National Registry of Evidence-Based Practices and Programs</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hierarchy_of_evidence&action=edit&section=7" title="Edit section: U.S. National Registry of Evidence-Based Practices and Programs"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>An assessment protocol has been developed by the U.S. National Registry of Evidence-Based Practices and Programs (NREPP). Evaluation under this protocol occurs only if an intervention has already had one or more positive outcomes, with a probability of less than .05, reported, if these have been published in a peer-reviewed journal or an evaluation report, and if documentation such as training materials has been made available. The NREPP evaluation, which assigns quality ratings from 0 to 4 to certain criteria, examines reliability and validity of outcome measures used in the research, evidence for intervention fidelity (predictable use of the treatment in the same way every time), levels of missing data and attrition, potential confounding variables, and the appropriateness of statistical handling, including sample size.<sup id="cite_ref-18" class="reference"><a href="#cite_note-18"><span class="cite-bracket">[</span>18<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="History">History</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hierarchy_of_evidence&action=edit&section=8" title="Edit section: History"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Canada">Canada</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hierarchy_of_evidence&action=edit&section=9" title="Edit section: Canada"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The term was first used in a 1979 report by the "Canadian Task Force on the Periodic Health Examination" (CTF) to "grade the effectiveness of an intervention according to the quality of evidence obtained".<sup id="cite_ref-CMA79_19-0" class="reference"><a href="#cite_note-CMA79-19"><span class="cite-bracket">[</span>19<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Page / location: 1195">: 1195 </span></sup> The task force used three levels, subdividing level II: </p> <ul><li>Level I: Evidence from at least one <a href="/wiki/Randomized_controlled_trial" title="Randomized controlled trial">randomized controlled trial</a>,</li> <li>Level II1: Evidence from at least one well designed <a href="/wiki/Cohort_study" title="Cohort study">cohort study</a> or <a href="/wiki/Case_control_study" class="mw-redirect" title="Case control study">case control study</a>, preferably from more than one center or research group.</li> <li>Level II2: Comparisons between times and places with or without the intervention</li> <li>Level III: Opinions of respected authorities, based on clinical experience, descriptive studies or reports of expert committees.</li></ul> <p>The CTF graded their recommendations into a 5-point A–E scale: A: Good level of evidence for the recommendation to consider a condition, B: Fair level of evidence for the recommendation to consider a condition, C: Poor level of evidence for the recommendation to consider a condition, D: Fair level evidence for the recommendation to exclude the condition, and E: Good level of evidence for the recommendation to exclude condition from consideration.<sup id="cite_ref-CMA79_19-1" class="reference"><a href="#cite_note-CMA79-19"><span class="cite-bracket">[</span>19<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Page / location: 1195">: 1195 </span></sup> The CTF updated their report in 1984,<sup id="cite_ref-CMA84_20-0" class="reference"><a href="#cite_note-CMA84-20"><span class="cite-bracket">[</span>20<span class="cite-bracket">]</span></a></sup> in 1986<sup id="cite_ref-CMA86_21-0" class="reference"><a href="#cite_note-CMA86-21"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup> and 1987.<sup id="cite_ref-CMA87_22-0" class="reference"><a href="#cite_note-CMA87-22"><span class="cite-bracket">[</span>22<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="United_States">United States</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hierarchy_of_evidence&action=edit&section=10" title="Edit section: United States"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In 1988, the <a href="/wiki/United_States_Preventive_Services_Task_Force" title="United States Preventive Services Task Force">United States Preventive Services Task Force</a> (USPSTF) came out with its guidelines based on the CTF using the same three levels, further subdividing level II.<sup id="cite_ref-USPrevServTaskForce_23-0" class="reference"><a href="#cite_note-USPrevServTaskForce-23"><span class="cite-bracket">[</span>23<span class="cite-bracket">]</span></a></sup> </p> <ul><li>Level I: Evidence obtained from at least one properly designed <a href="/wiki/Randomized_controlled_trial" title="Randomized controlled trial">randomized controlled trial</a>.</li> <li>Level II-1: Evidence obtained from well-designed controlled trials without <a href="/wiki/Randomization" title="Randomization">randomization</a>.</li> <li>Level II-2: Evidence obtained from well-designed <a href="/wiki/Cohort_study" title="Cohort study">cohort</a> or <a href="/wiki/Case-control" class="mw-redirect" title="Case-control">case-control</a> analytic studies, preferably from more than one center or research group.</li> <li>Level II-3: Evidence obtained from multiple <a href="/wiki/Time_series" title="Time series">time series</a> designs with or without the intervention. Dramatic results in uncontrolled trials might also be regarded as this type of evidence.</li> <li>Level III: Opinions of respected authorities, based on clinical experience, descriptive studies, or reports of expert committees.</li></ul> <p>Over the years many more grading systems have been described.<sup id="cite_ref-24" class="reference"><a href="#cite_note-24"><span class="cite-bracket">[</span>24<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="United_Kingdom">United Kingdom</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hierarchy_of_evidence&action=edit&section=11" title="Edit section: United Kingdom"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In September 2000, the Oxford (UK) <a href="/wiki/Centre_for_Evidence-Based_Medicine" title="Centre for Evidence-Based Medicine">Centre for Evidence-Based Medicine</a> (CEBM) Levels of Evidence published its guidelines for 'Levels' of evidence regarding claims about prognosis, diagnosis, treatment benefits, treatment harms, and screening. It not only addressed therapy and prevention, but also diagnostic tests, prognostic markers, or harm. The original CEBM Levels was first released for Evidence-Based On Call to make the process of finding evidence feasible and its results explicit. As published in 2009<sup id="cite_ref-25" class="reference"><a href="#cite_note-25"><span class="cite-bracket">[</span>25<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-FOOTNOTEBurns_el_al2011_26-0" class="reference"><a href="#cite_note-FOOTNOTEBurns_el_al2011-26"><span class="cite-bracket">[</span>26<span class="cite-bracket">]</span></a></sup> they are: </p> <ul><li>1a: <a href="/wiki/Systematic_reviews" class="mw-redirect" title="Systematic reviews">Systematic reviews</a> (with homogeneity) of randomized controlled trials</li> <li>1b: Individual randomized controlled trials (with narrow <a href="/wiki/Confidence_interval" title="Confidence interval">confidence interval</a>)</li> <li>1c: All or none (when all patients died before the treatment became available, but some now survive on it; or when some patients died before the treatment became available, but none now die on it.)</li> <li>2a: Systematic reviews (with homogeneity) of cohort studies</li> <li>2b: Individual cohort study or low quality randomized controlled trials (e.g. <80% follow-up)</li> <li>2c: "Outcomes" Research; ecological studies</li> <li>3a: Systematic review (with homogeneity) of case-control studies</li> <li>3b: Individual case-control study</li> <li>4: <a href="/wiki/Case_series" title="Case series">Case series</a> (and poor quality cohort and case-control studies)</li> <li>5: <a href="/wiki/Expert_opinion" class="mw-redirect" title="Expert opinion">Expert opinion</a> without explicit critical appraisal, or based on physiology, bench research or "<a href="/wiki/First_Principles" class="mw-redirect" title="First Principles">first principles</a>"</li></ul> <p>In 2011, an international team redesigned the Oxford CEBM Levels to make it more understandable and to take into account recent developments in evidence ranking schemes. The Levels have been used by patients, clinicians and also to develop clinical guidelines including recommendations for the optimal use of phototherapy and topical therapy in <a href="/wiki/Psoriasis" title="Psoriasis">psoriasis</a><sup id="cite_ref-27" class="reference"><a href="#cite_note-27"><span class="cite-bracket">[</span>27<span class="cite-bracket">]</span></a></sup> and guidelines for the use of the BCLC staging system for diagnosing and monitoring <a href="/wiki/Hepatocellular_carcinoma" title="Hepatocellular carcinoma">hepatocellular carcinoma</a> in Canada.<sup id="cite_ref-28" class="reference"><a href="#cite_note-28"><span class="cite-bracket">[</span>28<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Global">Global</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hierarchy_of_evidence&action=edit&section=12" title="Edit section: Global"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In 2007, the <a href="/wiki/World_Cancer_Research_Fund" class="mw-redirect" title="World Cancer Research Fund">World Cancer Research Fund</a> grading system described 4 levels: Convincing, probable, possible and insufficient evidence.<sup id="cite_ref-29" class="reference"><a href="#cite_note-29"><span class="cite-bracket">[</span>29<span class="cite-bracket">]</span></a></sup> All <a href="/wiki/Global_Burden_of_Disease_Study" title="Global Burden of Disease Study">Global Burden of Disease Studies</a> have used it to evaluate epidemiologic evidence supporting causal relationships.<sup id="cite_ref-30" class="reference"><a href="#cite_note-30"><span class="cite-bracket">[</span>30<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Proponents">Proponents</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hierarchy_of_evidence&action=edit&section=13" title="Edit section: Proponents"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In 1995 Wilson et al.,<sup id="cite_ref-31" class="reference"><a href="#cite_note-31"><span class="cite-bracket">[</span>31<span class="cite-bracket">]</span></a></sup> in 1996 Hadorn et al.<sup id="cite_ref-32" class="reference"><a href="#cite_note-32"><span class="cite-bracket">[</span>32<span class="cite-bracket">]</span></a></sup> and in 1996 Atkins et al.<sup id="cite_ref-33" class="reference"><a href="#cite_note-33"><span class="cite-bracket">[</span>33<span class="cite-bracket">]</span></a></sup> have described and defended various types of grading systems. </p> <div class="mw-heading mw-heading2"><h2 id="Criticism">Criticism</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hierarchy_of_evidence&action=edit&section=14" title="Edit section: Criticism"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In 2011, a systematic review of the critical literature found three kinds of criticism: procedural aspects of EBM (especially from Cartwright, Worrall and Howick),<sup id="cite_ref-34" class="reference"><a href="#cite_note-34"><span class="cite-bracket">[</span>34<span class="cite-bracket">]</span></a></sup> greater than expected fallibility of EBM (Ioaanidis and others), and EBM being incomplete as a <a href="/wiki/Philosophy_of_science" title="Philosophy of science">philosophy of science</a> (Ashcroft and others).<sup id="cite_ref-35" class="reference"><a href="#cite_note-35"><span class="cite-bracket">[</span>35<span class="cite-bracket">]</span></a></sup><sup class="noprint Inline-Template" style="margin-left:0.1em; white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Please_clarify" title="Wikipedia:Please clarify"><span title="The text near this tag may need clarification or removal of jargon. (March 2018)">clarification needed</span></a></i>]</sup> <a href="/wiki/Michael_Rawlins" title="Michael Rawlins">Rawlins</a><sup id="cite_ref-36" class="reference"><a href="#cite_note-36"><span class="cite-bracket">[</span>36<span class="cite-bracket">]</span></a></sup> and <a href="/wiki/Robyn_Bluhm" title="Robyn Bluhm">Bluhm</a> note, that EBM limits the ability of research results to inform the care of individual patients, and that to understand the causes of diseases both population-level and laboratory research are necessary. EBM hierarchy of evidence does not take into account research on the safety and efficacy of medical interventions. RCTs should be designed "to elucidate within-group variability, which can only be done if the hierarchy of evidence is replaced by a network that takes into account the relationship between epidemiological and laboratory research"<sup id="cite_ref-37" class="reference"><a href="#cite_note-37"><span class="cite-bracket">[</span>37<span class="cite-bracket">]</span></a></sup> </p><p>The hierarchy of evidence produced by a study design has been questioned, because guidelines have "failed to properly define key terms, weight the merits of certain non-randomized controlled trials, and employ a comprehensive list of study design limitations".<sup id="cite_ref-Gugiu_38-0" class="reference"><a href="#cite_note-Gugiu-38"><span class="cite-bracket">[</span>38<span class="cite-bracket">]</span></a></sup> </p><p>Stegenga has criticized specifically that meta-analyses are placed at the top of such hierarchies.<sup id="cite_ref-Stegenga2_39-0" class="reference"><a href="#cite_note-Stegenga2-39"><span class="cite-bracket">[</span>39<span class="cite-bracket">]</span></a></sup> The assumption that RCTs ought to be necessarily near the top of such hierarchies has been criticized by Worrall<sup id="cite_ref-40" class="reference"><a href="#cite_note-40"><span class="cite-bracket">[</span>40<span class="cite-bracket">]</span></a></sup> and Cartwright.<sup id="cite_ref-41" class="reference"><a href="#cite_note-41"><span class="cite-bracket">[</span>41<span class="cite-bracket">]</span></a></sup> </p><p>In 2005, <a href="/wiki/Ross_Upshur" title="Ross Upshur">Ross Upshur</a> said that EBM claims to be a normative guide to being a better physician, but is not a philosophical <a href="/wiki/Doctrine" title="Doctrine">doctrine</a>.<sup id="cite_ref-42" class="reference"><a href="#cite_note-42"><span class="cite-bracket">[</span>42<span class="cite-bracket">]</span></a></sup> </p><p>Borgerson in 2009 wrote that the justifications for the hierarchy levels are not absolute and do not <a href="/wiki/Epistemic" class="mw-redirect" title="Epistemic">epistemically</a> justify them, but that "medical researchers should pay closer attention to social mechanisms for managing pervasive biases".<sup id="cite_ref-43" class="reference"><a href="#cite_note-43"><span class="cite-bracket">[</span>43<span class="cite-bracket">]</span></a></sup> La Caze noted that <a href="/wiki/Basic_science" class="mw-redirect" title="Basic science">basic science</a> resides on the lower tiers of EBM though it "plays a role in specifying experiments, but also analysing and interpreting the data."<sup id="cite_ref-44" class="reference"><a href="#cite_note-44"><span class="cite-bracket">[</span>44<span class="cite-bracket">]</span></a></sup> </p><p>Concato said in 2004, that it allowed RCTs too much authority and that not all research questions could be answered through RCTs, either because of practical or because of ethical issues. Even when evidence is available from high-quality RCTs, evidence from other study types may still be relevant.<sup id="cite_ref-45" class="reference"><a href="#cite_note-45"><span class="cite-bracket">[</span>45<span class="cite-bracket">]</span></a></sup> Stegenga opined that evidence assessment schemes are unreasonably constraining and less informative than other schemes now available.<sup id="cite_ref-Stegenga_5-1" class="reference"><a href="#cite_note-Stegenga-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> </p><p>In his 2015 PhD Thesis dedicated to the study of the various hierarchies of evidence in medicine, Christopher J Blunt concludes that although modest interpretations such as those offered by La Caze's model, conditional hierarchies like GRADE, and heuristic approaches as defended by Howick et al all survive previous philosophical criticism, he argues that modest interpretations are so weak they are unhelpful for clinical practice. For example, "GRADE and similar conditional models omit clinically relevant information, such as information about variation in treatments' effects and the causes of different responses to therapy; and that heuristic approaches lack the necessary empirical support". Blunt further concludes that "hierarchies are a poor basis for the application of evidence in clinical practice", since the core assumptions behind hierarchies of evidence, that "information about average treatment effects backed by high-quality evidence can justify strong recommendations", is untenable, and hence the evidence from individuals studies should be appraised in isolation.<sup id="cite_ref-bluntphd2015_46-0" class="reference"><a href="#cite_note-bluntphd2015-46"><span class="cite-bracket">[</span>46<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hierarchy_of_evidence&action=edit&section=15" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239009302">.mw-parser-output .portalbox{padding:0;margin:0.5em 0;display:table;box-sizing:border-box;max-width:175px;list-style:none}.mw-parser-output .portalborder{border:1px solid var(--border-color-base,#a2a9b1);padding:0.1em;background:var(--background-color-neutral-subtle,#f8f9fa)}.mw-parser-output .portalbox-entry{display:table-row;font-size:85%;line-height:110%;height:1.9em;font-style:italic;font-weight:bold}.mw-parser-output .portalbox-image{display:table-cell;padding:0.2em;vertical-align:middle;text-align:center}.mw-parser-output .portalbox-link{display:table-cell;padding:0.2em 0.2em 0.2em 0.3em;vertical-align:middle}@media(min-width:720px){.mw-parser-output .portalleft{clear:left;float:left;margin:0.5em 1em 0.5em 0}.mw-parser-output .portalright{clear:right;float:right;margin:0.5em 0 0.5em 1em}}</style><ul role="navigation" aria-label="Portals" class="noprint portalbox portalborder portalright"> <li class="portalbox-entry"><span class="portalbox-image"><span class="noviewer" typeof="mw:File"><a href="/wiki/File:Nuvola_apps_kalzium.svg" class="mw-file-description"><img alt="icon" src="//upload.wikimedia.org/wikipedia/commons/thumb/8/8b/Nuvola_apps_kalzium.svg/28px-Nuvola_apps_kalzium.svg.png" decoding="async" width="28" height="28" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/8/8b/Nuvola_apps_kalzium.svg/42px-Nuvola_apps_kalzium.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/8/8b/Nuvola_apps_kalzium.svg/56px-Nuvola_apps_kalzium.svg.png 2x" data-file-width="128" data-file-height="128" /></a></span></span><span class="portalbox-link"><a href="/wiki/Portal:Science" title="Portal:Science">Science portal</a></span></li></ul> <ul><li><a href="/wiki/Evidence-based_practice" title="Evidence-based practice">Evidence-based practice</a></li> <li><a href="/wiki/Evidence-based_medicine" title="Evidence-based medicine">Evidence-based medicine</a></li> <li><a href="/wiki/Jadad_scale" title="Jadad scale">Jadad scale</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hierarchy_of_evidence&action=edit&section=16" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist"> <div class="mw-references-wrap mw-references-columns"><ol class="references"> <li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite id="CITEREFSiegfried2017" class="citation news cs1">Siegfried T (2017-11-13). <a rel="nofollow" class="external text" href="https://www.sciencenews.org/blog/context/critique-medical-evidence-hierarchies">"Philosophical critique exposes flaws in medical evidence hierarchies"</a>. <i>Science News</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2018-05-16</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Science+News&rft.atitle=Philosophical+critique+exposes+flaws+in+medical+evidence+hierarchies&rft.date=2017-11-13&rft.aulast=Siegfried&rft.aufirst=Tom&rft_id=https%3A%2F%2Fwww.sciencenews.org%2Fblog%2Fcontext%2Fcritique-medical-evidence-hierarchies&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-Shafee-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-Shafee_2-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFShafeeMasukumeKipersztokDas2017" class="citation journal cs1">Shafee, Thomas; Masukume, Gwinyai; Kipersztok, Lisa; Das, Diptanshu; Häggström, Mikael; Heilman, James (28 August 2017). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5847101">"Evolution of Wikipedia's medical content: past, present and future"</a>. <i>Journal of Epidemiology and Community Health</i>. <b>71</b> (11): jech–2016–208601. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1136%2Fjech-2016-208601">10.1136/jech-2016-208601</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0143-005X">0143-005X</a>. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5847101">5847101</a></span>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/28847845">28847845</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Epidemiology+and+Community+Health&rft.atitle=Evolution+of+Wikipedia%27s+medical+content%3A+past%2C+present+and+future&rft.volume=71&rft.issue=11&rft.pages=jech-2016-208601&rft.date=2017-08-28&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC5847101%23id-name%3DPMC&rft.issn=0143-005X&rft_id=info%3Apmid%2F28847845&rft_id=info%3Adoi%2F10.1136%2Fjech-2016-208601&rft.aulast=Shafee&rft.aufirst=Thomas&rft.au=Masukume%2C+Gwinyai&rft.au=Kipersztok%2C+Lisa&rft.au=Das%2C+Diptanshu&rft.au=H%C3%A4ggstr%C3%B6m%2C+Mikael&rft.au=Heilman%2C+James&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC5847101&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFStrausRichardsonGlasziouHaynes2005" class="citation book cs1">Straus SE, Richardson WS, Glasziou P, Haynes RB (2005). <i>Evidence-based Medicine: How to Practice and Teach EBM</i> (3rd ed.). Edinburgh: Churchill Livingstone. pp. 102–105. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0443074448" title="Special:BookSources/978-0443074448"><bdi>978-0443074448</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Evidence-based+Medicine%3A+How+to+Practice+and+Teach+EBM&rft.place=Edinburgh&rft.pages=102-105&rft.edition=3rd&rft.pub=Churchill+Livingstone&rft.date=2005&rft.isbn=978-0443074448&rft.aulast=Straus&rft.aufirst=SE&rft.au=Richardson%2C+WS&rft.au=Glasziou%2C+P&rft.au=Haynes%2C+RB&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-Golder_Loke_Bland_2011_p=e1001026-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-Golder_Loke_Bland_2011_p=e1001026_4-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGolderLokeBland2011" class="citation journal cs1">Golder, Su; Loke, Yoon K.; Bland, Martin (2011-05-03). Vandenbroucke, Jan P. (ed.). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3086872">"Meta-analyses of Adverse Effects Data Derived from Randomised Controlled Trials as Compared to Observational Studies: Methodological Overview"</a>. <i>PLOS Medicine</i>. <b>8</b> (5). Public Library of Science (PLoS): e1001026. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1371%2Fjournal.pmed.1001026">10.1371/journal.pmed.1001026</a></span>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/1549-1676">1549-1676</a>. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3086872">3086872</a></span>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/21559325">21559325</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=PLOS+Medicine&rft.atitle=Meta-analyses+of+Adverse+Effects+Data+Derived+from+Randomised+Controlled+Trials+as+Compared+to+Observational+Studies%3A+Methodological+Overview&rft.volume=8&rft.issue=5&rft.pages=e1001026&rft.date=2011-05-03&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC3086872%23id-name%3DPMC&rft.issn=1549-1676&rft_id=info%3Apmid%2F21559325&rft_id=info%3Adoi%2F10.1371%2Fjournal.pmed.1001026&rft.aulast=Golder&rft.aufirst=Su&rft.au=Loke%2C+Yoon+K.&rft.au=Bland%2C+Martin&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC3086872&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-Stegenga-5"><span class="mw-cite-backlink">^ <a href="#cite_ref-Stegenga_5-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Stegenga_5-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFStegenga2014" class="citation journal cs1">Stegenga J (October 2014). <a rel="nofollow" class="external text" href="https://www.academia.edu/27276221">"Down with the hierarchies"</a>. <i>Topoi</i>. <b>33</b> (2): 313–322. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2Fs11245-013-9189-4">10.1007/s11245-013-9189-4</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:109929514">109929514</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Topoi&rft.atitle=Down+with+the+hierarchies&rft.volume=33&rft.issue=2&rft.pages=313-322&rft.date=2014-10&rft_id=info%3Adoi%2F10.1007%2Fs11245-013-9189-4&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A109929514%23id-name%3DS2CID&rft.aulast=Stegenga&rft.aufirst=J&rft_id=https%3A%2F%2Fwww.academia.edu%2F27276221&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-green-6"><span class="mw-cite-backlink">^ <a href="#cite_ref-green_6-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-green_6-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGreenhalgh1997" class="citation journal cs1"><a href="/wiki/Trisha_Greenhalgh" title="Trisha Greenhalgh">Greenhalgh T</a> (July 1997). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2127173">"How to read a paper. Getting your bearings (deciding what the paper is about)"</a>. <i>BMJ</i>. <b>315</b> (7102): 243–246. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1136%2Fbmj.315.7102.243">10.1136/bmj.315.7102.243</a>. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2127173">2127173</a></span>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/9253275">9253275</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=BMJ&rft.atitle=How+to+read+a+paper.+Getting+your+bearings+%28deciding+what+the+paper+is+about%29&rft.volume=315&rft.issue=7102&rft.pages=243-246&rft.date=1997-07&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC2127173%23id-name%3DPMC&rft_id=info%3Apmid%2F9253275&rft_id=info%3Adoi%2F10.1136%2Fbmj.315.7102.243&rft.aulast=Greenhalgh&rft.aufirst=T&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC2127173&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-nci-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-nci_7-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFNational_Cancer_Instituten.d." class="citation web cs1">National Cancer Institute (n.d.). <a rel="nofollow" class="external text" href="https://www.cancer.gov/dictionary?CdrID=446533">"NCI Dictionary of Cancer Terms: Levels of evidence"</a>. US DHHS-National Institutes of Health<span class="reference-accessdate">. Retrieved <span class="nowrap">8 December</span> 2014</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=NCI+Dictionary+of+Cancer+Terms%3A+Levels+of+evidence&rft.pub=US+DHHS-National+Institutes+of+Health&rft.au=National+Cancer+Institute&rft_id=http%3A%2F%2Fwww.cancer.gov%2Fdictionary%3FCdrID%3D446533&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-dentalcare.com-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-dentalcare.com_8-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20160304091218/http://media.dentalcare.com/images/en-US/education/ce311/fig02.jpg">"Evidence-Based Decision Making: Introduction and Formulating Good Clinical Questions | Continuing Education Course | dentalcare.com Course Pages | DentalCare.com"</a>. <i>www.dentalcare.com</i>. Archived from <a rel="nofollow" class="external text" href="http://www.dentalcare.com/en-US/dental-education/continuing-education/ce311/ce311.aspx?ModuleName=coursecontent&PartID=4&SectionID=-1">the original</a> on 4 Mar 2016<span class="reference-accessdate">. Retrieved <span class="nowrap">2015-09-03</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=www.dentalcare.com&rft.atitle=Evidence-Based+Decision+Making%3A+Introduction+and+Formulating+Good+Clinical+Questions+%7C+Continuing+Education+Course+%7C+dentalcare.com+Course+Pages+%7C+DentalCare.com&rft_id=http%3A%2F%2Fwww.dentalcare.com%2Fen-US%2Fdental-education%2Fcontinuing-education%2Fce311%2Fce311.aspx%3FModuleName%3Dcoursecontent%26PartID%3D4%26SectionID%3D-1&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-Capho-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-Capho_9-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20160221222657/http://www.capho.org/blog/journey-research-levels-evidence">"The Journey of Research - Levels of Evidence | CAPhO"</a>. <i>www.capho.org</i>. Archived from <a rel="nofollow" class="external text" href="http://www.capho.org/blog/journey-research-levels-evidence">the original</a> on 21 February 2016<span class="reference-accessdate">. Retrieved <span class="nowrap">2015-09-03</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=www.capho.org&rft.atitle=The+Journey+of+Research+-+Levels+of+Evidence+%7C+CAPhO&rft_id=http%3A%2F%2Fwww.capho.org%2Fblog%2Fjourney-research-levels-evidence&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-10">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSchünemannBestVistOxman2003" class="citation journal cs1"><a href="/wiki/Holger_Jens_Sch%C3%BCnemann" title="Holger Jens Schünemann">Schünemann, HJ</a>; Best, D; Vist, G; Oxman, AD (2003). "Letters, numbers, symbols, and words: How best to communicate grades of evidence and recommendations?". <i>Canadian Medical Association Journal</i>. <b>169</b> (7): 677–680.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Canadian+Medical+Association+Journal&rft.atitle=Letters%2C+numbers%2C+symbols%2C+and+words%3A+How+best+to+communicate+grades+of+evidence+and+recommendations%3F&rft.volume=169&rft.issue=7&rft.pages=677-680&rft.date=2003&rft.aulast=Sch%C3%BCnemann&rft.aufirst=HJ&rft.au=Best%2C+D&rft.au=Vist%2C+G&rft.au=Oxman%2C+AD&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://gradepro.org/resources/#guidelines">"GRADEpro"</a>. <i>Gradepro.org</i><span class="reference-accessdate">. Retrieved <span class="nowrap">16 August</span> 2019</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Gradepro.org&rft.atitle=GRADEpro&rft_id=https%3A%2F%2Fgradepro.org%2Fresources%2F%23guidelines&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-12">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20160225142414/http://www.moh.gov.sa/endepts/Proofs/Pages/Guidelines.aspx">"Ministry of Health وزارة الصحة"</a>. Archived from <a rel="nofollow" class="external text" href="http://www.moh.gov.sa/endepts/Proofs/Pages/Guidelines.aspx">the original</a> on 2016-02-25.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Ministry+of+Health+%D9%88%D8%B2%D8%A7%D8%B1%D8%A9+%D8%A7%D9%84%D8%B5%D8%AD%D8%A9&rft_id=http%3A%2F%2Fwww.moh.gov.sa%2Fendepts%2FProofs%2FPages%2FGuidelines.aspx&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-grade3-13"><span class="mw-cite-backlink"><b><a href="#cite_ref-grade3_13-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBalshemHelfandSchünemannOxman2011" class="citation journal cs1">Balshem, H; Helfand, M; <a href="/wiki/Holger_Jens_Sch%C3%BCnemann" title="Holger Jens Schünemann">Schünemann, HJ</a>; Oxman, AD; Kunz, R; Brozek, J; Vist, GE; Falck-Ytter, Y; Meerpohl, J; Norris, S; Guyatt, GH (April 2011). <a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.jclinepi.2010.07.015">"GRADE guidelines 3: rating the quality of evidence – introduction"</a>. <i>Journal of Clinical Epidemiology</i>. <b>64</b> (4): 401–406. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.jclinepi.2010.07.015">10.1016/j.jclinepi.2010.07.015</a></span>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/21208779">21208779</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Clinical+Epidemiology&rft.atitle=GRADE+guidelines+3%3A+rating+the+quality+of+evidence+%E2%80%93+introduction&rft.volume=64&rft.issue=4&rft.pages=401-406&rft.date=2011-04&rft_id=info%3Adoi%2F10.1016%2Fj.jclinepi.2010.07.015&rft_id=info%3Apmid%2F21208779&rft.aulast=Balshem&rft.aufirst=H&rft.au=Helfand%2C+M&rft.au=Sch%C3%BCnemann%2C+HJ&rft.au=Oxman%2C+AD&rft.au=Kunz%2C+R&rft.au=Brozek%2C+J&rft.au=Vist%2C+GE&rft.au=Falck-Ytter%2C+Y&rft.au=Meerpohl%2C+J&rft.au=Norris%2C+S&rft.au=Guyatt%2C+GH&rft_id=https%3A%2F%2Fdoi.org%2F10.1016%252Fj.jclinepi.2010.07.015&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-14">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFReed_Siemieniuk_and_Gordon_Guyatt" class="citation web cs1">Reed Siemieniuk and Gordon Guyatt. <a rel="nofollow" class="external text" href="https://bestpractice.bmj.com/info/us/toolkit/learn-ebm/what-is-grade/">"What is GRADE?"</a>. <i>BMJ Best Practice</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2020-07-02</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=BMJ+Best+Practice&rft.atitle=What+is+GRADE%3F&rft.au=Reed+Siemieniuk+and+Gordon+Guyatt&rft_id=https%3A%2F%2Fbestpractice.bmj.com%2Finfo%2Fus%2Ftoolkit%2Flearn-ebm%2Fwhat-is-grade%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-15"><span class="mw-cite-backlink"><b><a href="#cite_ref-15">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGuyattSackettSinclairHayward1995" class="citation journal cs1">Guyatt GH, Sackett DL, Sinclair JC, Hayward R, Cook DJ, Cook RJ (December 1995). "Users' guides to the medical literature. IX. A method for grading health care recommendations. Evidence-Based Medicine Working Group". <i>JAMA</i>. <b>274</b> (22): 1800–1804. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1001%2Fjama.1995.03530220066035">10.1001/jama.1995.03530220066035</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/7500513">7500513</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=JAMA&rft.atitle=Users%27+guides+to+the+medical+literature.+IX.+A+method+for+grading+health+care+recommendations.+Evidence-Based+Medicine+Working+Group&rft.volume=274&rft.issue=22&rft.pages=1800-1804&rft.date=1995-12&rft_id=info%3Adoi%2F10.1001%2Fjama.1995.03530220066035&rft_id=info%3Apmid%2F7500513&rft.aulast=Guyatt&rft.aufirst=GH&rft.au=Sackett%2C+DL&rft.au=Sinclair%2C+JC&rft.au=Hayward%2C+R&rft.au=Cook%2C+DJ&rft.au=Cook%2C+RJ&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-16"><span class="mw-cite-backlink"><b><a href="#cite_ref-16">^</a></b></span> <span class="reference-text">Saunders, B., Berliner, L., & Hanson, R. (2004). Child physical and sexual abuse: Guidelines for treatments. Retrieved September 15, 2006, from <a rel="nofollow" class="external free" href="http://www.musc.edu/cvc.guidel.htm">http://www.musc.edu/cvc.guidel.htm</a><sup class="noprint Inline-Template"><span style="white-space: nowrap;">[<i><a href="/wiki/Wikipedia:Link_rot" title="Wikipedia:Link rot"><span title=" Dead link tagged September 2017">permanent dead link</span></a></i><span style="visibility:hidden; color:transparent; padding-left:2px">‍</span>]</span></sup></span> </li> <li id="cite_note-17"><span class="mw-cite-backlink"><b><a href="#cite_ref-17">^</a></b></span> <span class="reference-text">Khan, K.S., et al. (2001). CRD Report 4. Stage II. Conducting the review. phase 5. Study quality assessment. York, UK: Centre for Reviews and Dissemination, University of York. Retrieved July 20, 2007 from <a rel="nofollow" class="external free" href="http://www.york.ac.uk/inst/crd/pdf/crd_4ph5.pdf">http://www.york.ac.uk/inst/crd/pdf/crd_4ph5.pdf</a></span> </li> <li id="cite_note-18"><span class="mw-cite-backlink"><b><a href="#cite_ref-18">^</a></b></span> <span class="reference-text">National Registry of Evidence-Based Practices and Programs (2007). NREPP Review Criteria. Retrieved March 10, 2008 from <a rel="nofollow" class="external free" href="http://www.nrepp.samsha.gov/review-criteria.htm">http://www.nrepp.samsha.gov/review-criteria.htm</a><sup class="noprint Inline-Template"><span style="white-space: nowrap;">[<i><a href="/wiki/Wikipedia:Link_rot" title="Wikipedia:Link rot"><span title=" Dead link tagged September 2017">permanent dead link</span></a></i><span style="visibility:hidden; color:transparent; padding-left:2px">‍</span>]</span></sup></span> </li> <li id="cite_note-CMA79-19"><span class="mw-cite-backlink">^ <a href="#cite_ref-CMA79_19-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-CMA79_19-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCanadian_Task_Force_on_the_Periodic_Health_Examination1979" class="citation journal cs1">Canadian Task Force on the Periodic Health Examination (3 November 1979). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1704686">"Task Force Report: The periodic health examination"</a>. <i>Can Med Assoc J</i>. <b>121</b> (9): 1193–1254. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1704686">1704686</a></span>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/115569">115569</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Can+Med+Assoc+J&rft.atitle=Task+Force+Report%3A+The+periodic+health+examination&rft.volume=121&rft.issue=9&rft.pages=1193-1254&rft.date=1979-11-03&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC1704686%23id-name%3DPMC&rft_id=info%3Apmid%2F115569&rft.au=Canadian+Task+Force+on+the+Periodic+Health+Examination&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC1704686&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-CMA84-20"><span class="mw-cite-backlink"><b><a href="#cite_ref-CMA84_20-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCanadian_Task_Force_on_the_Periodic_Health_Examination1984" class="citation journal cs1">Canadian Task Force on the Periodic Health Examination (15 May 1984). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1483525">"Task Force Report: The periodic health examination. 2. 1984 update"</a>. <i>Can Med Assoc J</i>. <b>130</b> (10): 1278–1285. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1483525">1483525</a></span>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/6722691">6722691</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Can+Med+Assoc+J&rft.atitle=Task+Force+Report%3A+The+periodic+health+examination.+2.+1984+update&rft.volume=130&rft.issue=10&rft.pages=1278-1285&rft.date=1984-05-15&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC1483525%23id-name%3DPMC&rft_id=info%3Apmid%2F6722691&rft.au=Canadian+Task+Force+on+the+Periodic+Health+Examination&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC1483525&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-CMA86-21"><span class="mw-cite-backlink"><b><a href="#cite_ref-CMA86_21-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCanadian_Task_Force_on_the_Periodic_Health_Examination1986" class="citation journal cs1">Canadian Task Force on the Periodic Health Examination (15 May 1986). "Task Force Report: The periodic health examination. 3. 1986 update". <i>Can Med Assoc J</i>. <b>134</b> (10): 721–729.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Can+Med+Assoc+J&rft.atitle=Task+Force+Report%3A+The+periodic+health+examination.+3.+1986+update&rft.volume=134&rft.issue=10&rft.pages=721-729&rft.date=1986-05-15&rft.au=Canadian+Task+Force+on+the+Periodic+Health+Examination&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-CMA87-22"><span class="mw-cite-backlink"><b><a href="#cite_ref-CMA87_22-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCanadian_Task_Force_on_the_Periodic_Health_Examination1988" class="citation journal cs1">Canadian Task Force on the Periodic Health Examination (1 April 1988). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1267740">"Task Force Report: The periodic health examination. 2. 1987 update"</a>. <i>Can Med Assoc J</i>. <b>138</b> (7): 618–626. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1267740">1267740</a></span>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/3355931">3355931</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Can+Med+Assoc+J&rft.atitle=Task+Force+Report%3A+The+periodic+health+examination.+2.+1987+update&rft.volume=138&rft.issue=7&rft.pages=618-626&rft.date=1988-04-01&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC1267740%23id-name%3DPMC&rft_id=info%3Apmid%2F3355931&rft.au=Canadian+Task+Force+on+the+Periodic+Health+Examination&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC1267740&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-USPrevServTaskForce-23"><span class="mw-cite-backlink"><b><a href="#cite_ref-USPrevServTaskForce_23-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFU.S._Preventive_Services_Task_Force1989" class="citation book cs1">U.S. Preventive Services Task Force (1989). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=eQGJHgI_dR8C&pg=PR24"><i>Guide to clinical preventive services: report of the U.S. Preventive Services Task Force</i></a>. Diane Publishing. pp. 24–. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1568062976" title="Special:BookSources/978-1568062976"><bdi>978-1568062976</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Guide+to+clinical+preventive+services%3A+report+of+the+U.S.+Preventive+Services+Task+Force&rft.pages=24-&rft.pub=Diane+Publishing&rft.date=1989&rft.isbn=978-1568062976&rft.au=U.S.+Preventive+Services+Task+Force&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DeQGJHgI_dR8C%26pg%3DPR24&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span> Appendix A</span> </li> <li id="cite_note-24"><span class="mw-cite-backlink"><b><a href="#cite_ref-24">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWelsh2010" class="citation web cs1">Welsh, Judith (January 2010). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20160331104333/http://nihlibrary.ors.nih.gov/jw/levels_of_evidence.html">"Levels of evidence and analyzing the literature"</a>. National Institutes of Health Library. Archived from <a rel="nofollow" class="external text" href="http://nihlibrary.ors.nih.gov/jw/levels_of_evidence.html">the original</a> on 31 March 2016<span class="reference-accessdate">. Retrieved <span class="nowrap">9 September</span> 2015</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Levels+of+evidence+and+analyzing+the+literature&rft.pub=National+Institutes+of+Health+Library&rft.date=2010-01&rft.aulast=Welsh&rft.aufirst=Judith&rft_id=http%3A%2F%2Fnihlibrary.ors.nih.gov%2Fjw%2Flevels_of_evidence.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-25"><span class="mw-cite-backlink"><b><a href="#cite_ref-25">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.cebm.net/oxford-centre-evidence-based-medicine-levels-evidence-march-2009/">"Oxford Centre for Evidence-based Medicine – Levels of Evidence (March 2009)"</a>. <i>Centre for Evidence-Based Medicine</i>. 2009-06-11<span class="reference-accessdate">. Retrieved <span class="nowrap">25 March</span> 2015</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Centre+for+Evidence-Based+Medicine&rft.atitle=Oxford+Centre+for+Evidence-based+Medicine+%E2%80%93+Levels+of+Evidence+%28March+2009%29&rft.date=2009-06-11&rft_id=http%3A%2F%2Fwww.cebm.net%2Foxford-centre-evidence-based-medicine-levels-evidence-march-2009%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-FOOTNOTEBurns_el_al2011-26"><span class="mw-cite-backlink"><b><a href="#cite_ref-FOOTNOTEBurns_el_al2011_26-0">^</a></b></span> <span class="reference-text"><a href="#CITEREFBurns_el_al2011">Burns el al 2011</a>.</span> </li> <li id="cite_note-27"><span class="mw-cite-backlink"><b><a href="#cite_ref-27">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFOCEBM_Levels_of_Evidence_Working_Group2016" class="citation web cs1">OCEBM Levels of Evidence Working Group (May 2016). <a rel="nofollow" class="external text" href="http://www.cebm.net/index.aspx?o=5653">"The Oxford Levels of Evidence 2'<span class="cs1-kern-right"></span>"</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=The+Oxford+Levels+of+Evidence+2%27&rft.date=2016-05&rft.au=OCEBM+Levels+of+Evidence+Working+Group&rft_id=http%3A%2F%2Fwww.cebm.net%2Findex.aspx%3Fo%3D5653&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-28"><span class="mw-cite-backlink"><b><a href="#cite_ref-28">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPaulGalliniArchier2012" class="citation journal cs1">Paul, C.; Gallini, A.; Archier, E.; et al. (2012). "Evidence-Based Recommendations on Topical Treatment and Phototherapy of Psoriasis: Systematic Review and Expert Opinion of a Panel of Dermatologists". <i>Journal of the European Academy of Dermatology and Venereology</i>. <b>26</b> (Suppl 3): 1–10. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1111%2Fj.1468-3083.2012.04518.x">10.1111/j.1468-3083.2012.04518.x</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/22512675">22512675</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:36103291">36103291</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+the+European+Academy+of+Dermatology+and+Venereology&rft.atitle=Evidence-Based+Recommendations+on+Topical+Treatment+and+Phototherapy+of+Psoriasis%3A+Systematic+Review+and+Expert+Opinion+of+a+Panel+of+Dermatologists&rft.volume=26&rft.issue=Suppl+3&rft.pages=1-10&rft.date=2012&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A36103291%23id-name%3DS2CID&rft_id=info%3Apmid%2F22512675&rft_id=info%3Adoi%2F10.1111%2Fj.1468-3083.2012.04518.x&rft.aulast=Paul&rft.aufirst=C.&rft.au=Gallini%2C+A.&rft.au=Archier%2C+E.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-29"><span class="mw-cite-backlink"><b><a href="#cite_ref-29">^</a></b></span> <span class="reference-text">World Cancer Research Fund AICR. Food, Nutrition, and Physical Activity, and the Prevention of Cancer: A Global Perspective. American Institute for Cancer Research, Washington, DC; 2007</span> </li> <li id="cite_note-30"><span class="mw-cite-backlink"><b><a href="#cite_ref-30">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLimVosFlaxmanDanaei2012" class="citation journal cs1">Lim, Stephen S; Vos, Theo; Flaxman, Abraham D; Danaei, Goodarz; Shibuya, Kenji; Adair-Rohani, Heather; Almazroa, Mohammad A; Amann, Markus; Anderson, H Ross; Andrews, Kathryn G; Aryee, Martin; Atkinson, Charles; Bacchus, Loraine J; Bahalim, Adil N; <a href="/wiki/Kalpana_Balakrishnan" title="Kalpana Balakrishnan">Balakrishnan, Kalpana</a>; Balmes, John; Barker-Collo, Suzanne; Baxter, Amanda; Bell, Michelle L; Blore, Jed D; Blyth, Fiona; Bonner, Carissa; Borges, Guilherme; Bourne, Rupert; Boussinesq, Michel; Brauer, Michael; Brooks, Peter; Bruce, Nigel G; Brunekreef, Bert; et al. (2012). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4156511">"A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990–2010: A systematic analysis for the Global Burden of Disease Study 2010"</a>. <i>The Lancet</i>. <b>380</b> (9859): 2224–2260. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2FS0140-6736%2812%2961766-8">10.1016/S0140-6736(12)61766-8</a>. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4156511">4156511</a></span>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/23245609">23245609</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Lancet&rft.atitle=A+comparative+risk+assessment+of+burden+of+disease+and+injury+attributable+to+67+risk+factors+and+risk+factor+clusters+in+21+regions%2C+1990%E2%80%932010%3A+A+systematic+analysis+for+the+Global+Burden+of+Disease+Study+2010&rft.volume=380&rft.issue=9859&rft.pages=2224-2260&rft.date=2012&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC4156511%23id-name%3DPMC&rft_id=info%3Apmid%2F23245609&rft_id=info%3Adoi%2F10.1016%2FS0140-6736%2812%2961766-8&rft.aulast=Lim&rft.aufirst=Stephen+S&rft.au=Vos%2C+Theo&rft.au=Flaxman%2C+Abraham+D&rft.au=Danaei%2C+Goodarz&rft.au=Shibuya%2C+Kenji&rft.au=Adair-Rohani%2C+Heather&rft.au=Almazroa%2C+Mohammad+A&rft.au=Amann%2C+Markus&rft.au=Anderson%2C+H+Ross&rft.au=Andrews%2C+Kathryn+G&rft.au=Aryee%2C+Martin&rft.au=Atkinson%2C+Charles&rft.au=Bacchus%2C+Loraine+J&rft.au=Bahalim%2C+Adil+N&rft.au=Balakrishnan%2C+Kalpana&rft.au=Balmes%2C+John&rft.au=Barker-Collo%2C+Suzanne&rft.au=Baxter%2C+Amanda&rft.au=Bell%2C+Michelle+L&rft.au=Blore%2C+Jed+D&rft.au=Blyth%2C+Fiona&rft.au=Bonner%2C+Carissa&rft.au=Borges%2C+Guilherme&rft.au=Bourne%2C+Rupert&rft.au=Boussinesq%2C+Michel&rft.au=Brauer%2C+Michael&rft.au=Brooks%2C+Peter&rft.au=Bruce%2C+Nigel+G&rft.au=Brunekreef%2C+Bert&rft.au=Bryan-Hancock%2C+Claire&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC4156511&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-31"><span class="mw-cite-backlink"><b><a href="#cite_ref-31">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWilson1995" class="citation journal cs1">Wilson, Mark C (1995). "Users' guides to the medical literature. VIII. How to use clinical practice guidelines. B. what are the recommendations and will they help you in caring for your patients? The evidence-based medicine working group". <i>JAMA</i>. <b>274</b> (20): 1630–1632. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1001%2Fjama.1995.03530200066040">10.1001/jama.1995.03530200066040</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/7474251">7474251</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:8593521">8593521</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=JAMA&rft.atitle=Users%27+guides+to+the+medical+literature.+VIII.+How+to+use+clinical+practice+guidelines.+B.+what+are+the+recommendations+and+will+they+help+you+in+caring+for+your+patients%3F+The+evidence-based+medicine+working+group&rft.volume=274&rft.issue=20&rft.pages=1630-1632&rft.date=1995&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A8593521%23id-name%3DS2CID&rft_id=info%3Apmid%2F7474251&rft_id=info%3Adoi%2F10.1001%2Fjama.1995.03530200066040&rft.aulast=Wilson&rft.aufirst=Mark+C&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-32"><span class="mw-cite-backlink"><b><a href="#cite_ref-32">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHadornBakerHodgesHicks1996" class="citation journal cs1">Hadorn, David C; Baker, David; Hodges, James S; Hicks, Nicholas (1996). "Rating the quality of evidence for clinical practice guidelines". <i>Journal of Clinical Epidemiology</i>. <b>49</b> (7): 749–754. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2F0895-4356%2896%2900019-4">10.1016/0895-4356(96)00019-4</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/8691224">8691224</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Clinical+Epidemiology&rft.atitle=Rating+the+quality+of+evidence+for+clinical+practice+guidelines&rft.volume=49&rft.issue=7&rft.pages=749-754&rft.date=1996&rft_id=info%3Adoi%2F10.1016%2F0895-4356%2896%2900019-4&rft_id=info%3Apmid%2F8691224&rft.aulast=Hadorn&rft.aufirst=David+C&rft.au=Baker%2C+David&rft.au=Hodges%2C+James+S&rft.au=Hicks%2C+Nicholas&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-33"><span class="mw-cite-backlink"><b><a href="#cite_ref-33">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAtkinsBestBrissEccles2004" class="citation journal cs1">Atkins, D; Best, D; Briss, P. A; Eccles, M; Falck-Ytter, Y; Flottorp, S; Guyatt, G. H; Harbour, R. T; Haugh, M. C; Henry, D; Hill, S; Jaeschke, R; Leng, G; Liberati, A; Magrini, N; Mason, J; Middleton, P; Mrukowicz, J; O'Connell, D; Oxman, A. D; Phillips, B; Schünemann, H. J; Edejer, T; Varonen, H; Vist, G. E; Williams Jr, J. W; Zaza, S; GRADE Working Group (2004). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC428525">"Grading quality of evidence and strength of recommendations"</a>. <i>BMJ</i>. <b>328</b> (7454): 1490. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1136%2Fbmj.328.7454.1490">10.1136/bmj.328.7454.1490</a>. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC428525">428525</a></span>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/15205295">15205295</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=BMJ&rft.atitle=Grading+quality+of+evidence+and+strength+of+recommendations&rft.volume=328&rft.issue=7454&rft.pages=1490&rft.date=2004&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC428525%23id-name%3DPMC&rft_id=info%3Apmid%2F15205295&rft_id=info%3Adoi%2F10.1136%2Fbmj.328.7454.1490&rft.aulast=Atkins&rft.aufirst=D&rft.au=Best%2C+D&rft.au=Briss%2C+P.+A&rft.au=Eccles%2C+M&rft.au=Falck-Ytter%2C+Y&rft.au=Flottorp%2C+S&rft.au=Guyatt%2C+G.+H&rft.au=Harbour%2C+R.+T&rft.au=Haugh%2C+M.+C&rft.au=Henry%2C+D&rft.au=Hill%2C+S&rft.au=Jaeschke%2C+R&rft.au=Leng%2C+G&rft.au=Liberati%2C+A&rft.au=Magrini%2C+N&rft.au=Mason%2C+J&rft.au=Middleton%2C+P&rft.au=Mrukowicz%2C+J&rft.au=O%27Connell%2C+D&rft.au=Oxman%2C+A.+D&rft.au=Phillips%2C+B&rft.au=Sch%C3%BCnemann%2C+H.+J&rft.au=Edejer%2C+T&rft.au=Varonen%2C+H&rft.au=Vist%2C+G.+E&rft.au=Williams+Jr%2C+J.+W&rft.au=Zaza%2C+S&rft.au=GRADE+Working+Group&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC428525&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-34"><span class="mw-cite-backlink"><b><a href="#cite_ref-34">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJeremy_Howick2011" class="citation book cs1">Jeremy Howick (2011-02-23). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=O8djbHBva5IC&pg=PA15"><i>The Philosophy of Evidence-based Medicine</i></a>. John Wiley & Sons. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-4443-4266-6" title="Special:BookSources/978-1-4443-4266-6"><bdi>978-1-4443-4266-6</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Philosophy+of+Evidence-based+Medicine&rft.pub=John+Wiley+%26+Sons&rft.date=2011-02-23&rft.isbn=978-1-4443-4266-6&rft.au=Jeremy+Howick&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DO8djbHBva5IC%26pg%3DPA15&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-35"><span class="mw-cite-backlink"><b><a href="#cite_ref-35">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSolomon2011" class="citation journal cs1"><a href="/wiki/Miriam_Solomon" title="Miriam Solomon">Solomon M</a> (October 2011). <a rel="nofollow" class="external text" href="http://philsci-archive.pitt.edu/4793/1/EBM_Chapter.doc">"Just a paradigm: evidence-based medicine in epistemological context"</a>. <i>European Journal for Philosophy of Science</i>. <b>1</b> (3). <a href="/wiki/Springer_Science%2BBusiness_Media" title="Springer Science+Business Media">Springer</a>: 451–466. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2Fs13194-011-0034-6">10.1007/s13194-011-0034-6</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:170193949">170193949</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=European+Journal+for+Philosophy+of+Science&rft.atitle=Just+a+paradigm%3A+evidence-based+medicine+in+epistemological+context&rft.volume=1&rft.issue=3&rft.pages=451-466&rft.date=2011-10&rft_id=info%3Adoi%2F10.1007%2Fs13194-011-0034-6&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A170193949%23id-name%3DS2CID&rft.aulast=Solomon&rft.aufirst=Miriam&rft_id=http%3A%2F%2Fphilsci-archive.pitt.edu%2F4793%2F1%2FEBM_Chapter.doc&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-36"><span class="mw-cite-backlink"><b><a href="#cite_ref-36">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFRawlins2008" class="citation journal cs1"><a href="/wiki/Michael_Rawlins" title="Michael Rawlins">Rawlins M</a> (December 2008). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4954394">"De Testimonio: on the evidence for decisions about the use of therapeutic interventions"</a>. <i>Clinical Medicine</i>. <b>8</b> (6). <a href="/wiki/Royal_College_of_Physicians" title="Royal College of Physicians">Royal College of Physicians</a>: 579–588. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.7861%2Fclinmedicine.8-6-579">10.7861/clinmedicine.8-6-579</a>. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4954394">4954394</a></span>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/19149278">19149278</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Clinical+Medicine&rft.atitle=De+Testimonio%3A+on+the+evidence+for+decisions+about+the+use+of+therapeutic+interventions&rft.volume=8&rft.issue=6&rft.pages=579-588&rft.date=2008-12&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC4954394%23id-name%3DPMC&rft_id=info%3Apmid%2F19149278&rft_id=info%3Adoi%2F10.7861%2Fclinmedicine.8-6-579&rft.aulast=Rawlins&rft.aufirst=M&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC4954394&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-37"><span class="mw-cite-backlink"><b><a href="#cite_ref-37">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBluhm2011" class="citation journal cs1"><a href="/wiki/Robyn_Bluhm" title="Robyn Bluhm">Bluhm R</a> (October 2011). "From hierarchy to network: a richer view of evidence for evidence-based medicine". <i>Perspectives in Biology and Medicine</i>. <b>48</b> (4). <a href="/wiki/Johns_Hopkins_University_Press" title="Johns Hopkins University Press">Johns Hopkins University Press</a>: 535–547. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1353%2Fpbm.2005.0082">10.1353/pbm.2005.0082</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/16227665">16227665</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:1156284">1156284</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Perspectives+in+Biology+and+Medicine&rft.atitle=From+hierarchy+to+network%3A+a+richer+view+of+evidence+for+evidence-based+medicine&rft.volume=48&rft.issue=4&rft.pages=535-547&rft.date=2011-10&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A1156284%23id-name%3DS2CID&rft_id=info%3Apmid%2F16227665&rft_id=info%3Adoi%2F10.1353%2Fpbm.2005.0082&rft.aulast=Bluhm&rft.aufirst=R&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-Gugiu-38"><span class="mw-cite-backlink"><b><a href="#cite_ref-Gugiu_38-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGugiu,_PCWestine,_CDCoryn,_CLHobson,_KA2012" class="citation journal cs1">Gugiu, PC; Westine, CD; Coryn, CL; Hobson, KA (3 April 2012). "An application of a new evidence grading system to research on the chronic care model". <i>Eval Health Prof</i>. <b>36</b> (1): 3–43. <a href="/wiki/CiteSeerX_(identifier)" class="mw-redirect" title="CiteSeerX (identifier)">CiteSeerX</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1016.5990">10.1.1.1016.5990</a></span>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1177%2F0163278712436968">10.1177/0163278712436968</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/22473325">22473325</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:206452088">206452088</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Eval+Health+Prof&rft.atitle=An+application+of+a+new+evidence+grading+system+to+research+on+the+chronic+care+model&rft.volume=36&rft.issue=1&rft.pages=3-43&rft.date=2012-04-03&rft_id=https%3A%2F%2Fciteseerx.ist.psu.edu%2Fviewdoc%2Fsummary%3Fdoi%3D10.1.1.1016.5990%23id-name%3DCiteSeerX&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A206452088%23id-name%3DS2CID&rft_id=info%3Apmid%2F22473325&rft_id=info%3Adoi%2F10.1177%2F0163278712436968&rft.au=Gugiu%2C+PC&rft.au=Westine%2C+CD&rft.au=Coryn%2C+CL&rft.au=Hobson%2C+KA&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-Stegenga2-39"><span class="mw-cite-backlink"><b><a href="#cite_ref-Stegenga2_39-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFStegenga2011" class="citation journal cs1">Stegenga, J (2011). <a rel="nofollow" class="external text" href="https://www.academia.edu/2310140">"Is meta-analysis the platinum standard of evidence?"</a>. <i>Stud Hist Philos Biol Biomed Sci</i>. <b>42</b> (4): 497–507. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.shpsc.2011.07.003">10.1016/j.shpsc.2011.07.003</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/22035723">22035723</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Stud+Hist+Philos+Biol+Biomed+Sci&rft.atitle=Is+meta-analysis+the+platinum+standard+of+evidence%3F&rft.volume=42&rft.issue=4&rft.pages=497-507&rft.date=2011&rft_id=info%3Adoi%2F10.1016%2Fj.shpsc.2011.07.003&rft_id=info%3Apmid%2F22035723&rft.aulast=Stegenga&rft.aufirst=J&rft_id=https%3A%2F%2Fwww.academia.edu%2F2310140&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-40"><span class="mw-cite-backlink"><b><a href="#cite_ref-40">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWorrall2002" class="citation journal cs1">Worrall, John (2002). "What Evidence in Evidence-Based Medicine?". <i>Philosophy of Science</i>. <b>69</b>: S316–S330. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F341855">10.1086/341855</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:55078796">55078796</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Philosophy+of+Science&rft.atitle=What+Evidence+in+Evidence-Based+Medicine%3F&rft.volume=69&rft.pages=S316-S330&rft.date=2002&rft_id=info%3Adoi%2F10.1086%2F341855&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A55078796%23id-name%3DS2CID&rft.aulast=Worrall&rft.aufirst=John&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-41"><span class="mw-cite-backlink"><b><a href="#cite_ref-41">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCartwright2007" class="citation journal cs1">Cartwright, Nancy (2007). <a rel="nofollow" class="external text" href="http://dro.dur.ac.uk/17541/1/17541.pdf">"Are RCTs the Gold Standard?"</a> <span class="cs1-format">(PDF)</span>. <i>BioSocieties</i>. <b>2</b>: 11–20. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1017%2Fs1745855207005029">10.1017/s1745855207005029</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:145592046">145592046</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=BioSocieties&rft.atitle=Are+RCTs+the+Gold+Standard%3F&rft.volume=2&rft.pages=11-20&rft.date=2007&rft_id=info%3Adoi%2F10.1017%2Fs1745855207005029&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A145592046%23id-name%3DS2CID&rft.aulast=Cartwright&rft.aufirst=Nancy&rft_id=http%3A%2F%2Fdro.dur.ac.uk%2F17541%2F1%2F17541.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-42"><span class="mw-cite-backlink"><b><a href="#cite_ref-42">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFUpshur2005" class="citation journal cs1"><a href="/wiki/Ross_Upshur" title="Ross Upshur">Upshur RE</a> (Autumn 2005). "Looking for rules in a world of exceptions: reflections on evidence-based practice". <i>Perspectives in Biology and Medicine</i>. <b>48</b> (4). <a href="/wiki/Johns_Hopkins_University_Press" title="Johns Hopkins University Press">Johns Hopkins University Press</a>: 477–489. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1353%2Fpbm.2005.0098">10.1353/pbm.2005.0098</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/16227661">16227661</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:36678226">36678226</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Perspectives+in+Biology+and+Medicine&rft.atitle=Looking+for+rules+in+a+world+of+exceptions%3A+reflections+on+evidence-based+practice&rft.ssn=fall&rft.volume=48&rft.issue=4&rft.pages=477-489&rft.date=2005&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A36678226%23id-name%3DS2CID&rft_id=info%3Apmid%2F16227661&rft_id=info%3Adoi%2F10.1353%2Fpbm.2005.0098&rft.aulast=Upshur&rft.aufirst=RE&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-43"><span class="mw-cite-backlink"><b><a href="#cite_ref-43">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBorgerson2009" class="citation journal cs1">Borgerson K (Spring 2009). <a rel="nofollow" class="external text" href="http://DalSpace.library.dal.ca/bitstream/10222/35695/1/project_muse_263282.pdf">"Valuing evidence: bias and the evidence hierarchy of evidence-based medicine"</a> <span class="cs1-format">(PDF)</span>. <i>Perspectives in Biology and Medicine</i>. <b>52</b> (2). <a href="/wiki/Johns_Hopkins_University_Press" title="Johns Hopkins University Press">Johns Hopkins University Press</a>: 218–233. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1353%2Fpbm.0.0086">10.1353/pbm.0.0086</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/19395821">19395821</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:38324417">38324417</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Perspectives+in+Biology+and+Medicine&rft.atitle=Valuing+evidence%3A+bias+and+the+evidence+hierarchy+of+evidence-based+medicine&rft.ssn=spring&rft.volume=52&rft.issue=2&rft.pages=218-233&rft.date=2009&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A38324417%23id-name%3DS2CID&rft_id=info%3Apmid%2F19395821&rft_id=info%3Adoi%2F10.1353%2Fpbm.0.0086&rft.aulast=Borgerson&rft.aufirst=K&rft_id=http%3A%2F%2FDalSpace.library.dal.ca%2Fbitstream%2F10222%2F35695%2F1%2Fproject_muse_263282.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-44"><span class="mw-cite-backlink"><b><a href="#cite_ref-44">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLa_Caze2011" class="citation journal cs1">La Caze A (January 2011). "The role of basic science in evidence-based medicine". <i><a href="/wiki/Biology_and_Philosophy" class="mw-redirect" title="Biology and Philosophy">Biology & Philosophy</a></i>. <b>26</b> (1). <a href="/wiki/Springer_Science%2BBusiness_Media" title="Springer Science+Business Media">Springer</a>: 81–98. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2Fs10539-010-9231-5">10.1007/s10539-010-9231-5</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:189902678">189902678</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Biology+%26+Philosophy&rft.atitle=The+role+of+basic+science+in+evidence-based+medicine&rft.volume=26&rft.issue=1&rft.pages=81-98&rft.date=2011-01&rft_id=info%3Adoi%2F10.1007%2Fs10539-010-9231-5&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A189902678%23id-name%3DS2CID&rft.aulast=La+Caze&rft.aufirst=Adam&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-45"><span class="mw-cite-backlink"><b><a href="#cite_ref-45">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFConcato2004" class="citation journal cs1">Concato J (July 2004). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC534936">"Observational versus experimental studies: what's the evidence for a hierarchy?"</a>. <i>NeuroRx</i>. <b>1</b> (3). <a href="/wiki/Springer_Science%2BBusiness_Media" title="Springer Science+Business Media">Springer</a>: 341–347. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1602%2Fneurorx.1.3.341">10.1602/neurorx.1.3.341</a>. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC534936">534936</a></span>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/15717036">15717036</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=NeuroRx&rft.atitle=Observational+versus+experimental+studies%3A+what%27s+the+evidence+for+a+hierarchy%3F&rft.volume=1&rft.issue=3&rft.pages=341-347&rft.date=2004-07&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC534936%23id-name%3DPMC&rft_id=info%3Apmid%2F15717036&rft_id=info%3Adoi%2F10.1602%2Fneurorx.1.3.341&rft.aulast=Concato&rft.aufirst=J&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC534936&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> <li id="cite_note-bluntphd2015-46"><span class="mw-cite-backlink"><b><a href="#cite_ref-bluntphd2015_46-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBlunt2015" class="citation thesis cs1">Blunt, Christopher J (September 2015). <a rel="nofollow" class="external text" href="http://etheses.lse.ac.uk/id/eprint/3284"><i>Hierarchies of evidence in evidence-based medicine</i></a>. <i>PhD Thesis</i> (phd). London School of Economics and Political Science.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adissertation&rft.title=Hierarchies+of+evidence+in+evidence-based+medicine&rft.inst=London+School+of+Economics+and+Political+Science&rft.date=2015-09&rft.aulast=Blunt&rft.aufirst=Christopher+J&rft_id=http%3A%2F%2Fetheses.lse.ac.uk%2Fid%2Feprint%2F3284&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></span> </li> </ol></div></div> <div class="mw-heading mw-heading3"><h3 id="Works_cited">Works cited</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hierarchy_of_evidence&action=edit&section=17" title="Edit section: Works cited"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239549316">.mw-parser-output .refbegin{margin-bottom:0.5em}.mw-parser-output .refbegin-hanging-indents>ul{margin-left:0}.mw-parser-output .refbegin-hanging-indents>ul>li{margin-left:0;padding-left:3.2em;text-indent:-3.2em}.mw-parser-output .refbegin-hanging-indents ul,.mw-parser-output .refbegin-hanging-indents ul li{list-style:none}@media(max-width:720px){.mw-parser-output .refbegin-hanging-indents>ul>li{padding-left:1.6em;text-indent:-1.6em}}.mw-parser-output .refbegin-columns{margin-top:0.3em}.mw-parser-output .refbegin-columns ul{margin-top:0}.mw-parser-output .refbegin-columns li{page-break-inside:avoid;break-inside:avoid-column}@media screen{.mw-parser-output .refbegin{font-size:90%}}</style><div class="refbegin" style=""> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBurns_el_al2011" class="citation journal cs1">Burns, Patricia B.; Rohrich, Rod J.; Chung, Kevin C. (July 2011). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3124652">"The Levels of Evidence and Their Role in Evidence-Based Medicine"</a>. <i><a href="/wiki/Plastic_and_Reconstructive_Surgery" title="Plastic and Reconstructive Surgery">Plastic and Reconstructive Surgery</a></i>. <b>128</b> (1): 305–310. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1097%2FPRS.0b013e318219c171">10.1097/PRS.0b013e318219c171</a>. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3124652">3124652</a></span>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/21701348">21701348</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Plastic+and+Reconstructive+Surgery&rft.atitle=The+Levels+of+Evidence+and+Their+Role+in+Evidence-Based+Medicine&rft.volume=128&rft.issue=1&rft.pages=305-310&rft.date=2011-07&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC3124652%23id-name%3DPMC&rft_id=info%3Apmid%2F21701348&rft_id=info%3Adoi%2F10.1097%2FPRS.0b013e318219c171&rft.aulast=Burns&rft.aufirst=Patricia+B.&rft.au=Rohrich%2C+Rod+J.&rft.au=Chung%2C+Kevin+C.&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC3124652&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span></li></ul> </div> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hierarchy_of_evidence&action=edit&section=18" title="Edit section: External links"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a rel="nofollow" class="external text" href="https://www.cebm.ox.ac.uk/resources/levels-of-evidence/ocebm-levels-of-evidence">Evidence levels with explanations</a> – entry in the Centre for Evidence-Based Medicine</li> <li><a rel="nofollow" class="external text" href="https://researchguides.dartmouth.edu/c.php?g=944702&p=6833672">Evidence-based medicine resources page</a> – with a diagram showing different levels of evidence forming a pyramid</li> <li><a rel="nofollow" class="external text" href="https://cjblunt.com/hierarchies-evidence/">Systematic database of 195 hierarchies of evidence in medicine up to 08/10/2020</a> by Christopher J Blunt for his PhD Thesis.</li></ul> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><style data-mw-deduplicate="TemplateStyles:r1236075235">.mw-parser-output .navbox{box-sizing:border-box;border:1px solid #a2a9b1;width:100%;clear:both;font-size:88%;text-align:center;padding:1px;margin:1em auto 0}.mw-parser-output .navbox .navbox{margin-top:0}.mw-parser-output .navbox+.navbox,.mw-parser-output .navbox+.navbox-styles+.navbox{margin-top:-1px}.mw-parser-output .navbox-inner,.mw-parser-output .navbox-subgroup{width:100%}.mw-parser-output .navbox-group,.mw-parser-output .navbox-title,.mw-parser-output .navbox-abovebelow{padding:0.25em 1em;line-height:1.5em;text-align:center}.mw-parser-output .navbox-group{white-space:nowrap;text-align:right}.mw-parser-output .navbox,.mw-parser-output .navbox-subgroup{background-color:#fdfdfd}.mw-parser-output .navbox-list{line-height:1.5em;border-color:#fdfdfd}.mw-parser-output .navbox-list-with-group{text-align:left;border-left-width:2px;border-left-style:solid}.mw-parser-output tr+tr>.navbox-abovebelow,.mw-parser-output tr+tr>.navbox-group,.mw-parser-output tr+tr>.navbox-image,.mw-parser-output tr+tr>.navbox-list{border-top:2px solid #fdfdfd}.mw-parser-output .navbox-title{background-color:#ccf}.mw-parser-output .navbox-abovebelow,.mw-parser-output .navbox-group,.mw-parser-output .navbox-subgroup .navbox-title{background-color:#ddf}.mw-parser-output .navbox-subgroup .navbox-group,.mw-parser-output .navbox-subgroup .navbox-abovebelow{background-color:#e6e6ff}.mw-parser-output .navbox-even{background-color:#f7f7f7}.mw-parser-output .navbox-odd{background-color:transparent}.mw-parser-output .navbox .hlist td dl,.mw-parser-output .navbox .hlist td ol,.mw-parser-output .navbox .hlist td ul,.mw-parser-output .navbox td.hlist dl,.mw-parser-output .navbox td.hlist ol,.mw-parser-output .navbox td.hlist ul{padding:0.125em 0}.mw-parser-output .navbox .navbar{display:block;font-size:100%}.mw-parser-output .navbox-title .navbar{float:left;text-align:left;margin-right:0.5em}body.skin--responsive .mw-parser-output .navbox-image img{max-width:none!important}@media print{body.ns-0 .mw-parser-output .navbox{display:none!important}}</style></div><div role="navigation" class="navbox" aria-labelledby="Evidence-based_practice" style="padding:3px"><table class="nowraplinks mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Evidence-based_practice" title="Template:Evidence-based practice"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Evidence-based_practice" title="Template talk:Evidence-based practice"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Evidence-based_practice" title="Special:EditPage/Template:Evidence-based practice"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Evidence-based_practice" style="font-size:114%;margin:0 4em"><a href="/wiki/Evidence-based_practice" title="Evidence-based practice">Evidence-based practice</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Key terms</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Evidence-based_practice" title="Evidence-based practice">Evidence-based practice</a></li> <li><a class="mw-selflink selflink">Hierarchy of evidence</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Applications</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Effective_altruism" title="Effective altruism">Effective altruism</a></li> <li><a href="/wiki/Evidence-based_assessment" title="Evidence-based assessment">Evidence-based assessment</a></li> <li><a href="/wiki/Evidence-based_conservation" title="Evidence-based conservation">Evidence-based conservation</a></li> <li><a href="/wiki/Evidence-based_dentistry" title="Evidence-based dentistry">Evidence-based dentistry</a></li> <li><a href="/wiki/Evidence-based_design" title="Evidence-based design">Evidence-based design</a></li> <li><a href="/wiki/Evidence-based_education" title="Evidence-based education">Evidence-based education</a></li> <li><a href="/wiki/Evidence-based_legislation" title="Evidence-based legislation">Evidence-based legislation</a></li> <li><a href="/wiki/Evidence-based_library_and_information_practice" title="Evidence-based library and information practice">Evidence-based library and information practice</a></li> <li><a href="/wiki/Evidence-based_management" title="Evidence-based management">Evidence-based management</a></li> <li><a href="/wiki/Evidence-based_medical_ethics" title="Evidence-based medical ethics">Evidence-based medical ethics</a></li> <li><a href="/wiki/Evidence-based_medicine" title="Evidence-based medicine">Evidence-based medicine</a></li> <li><a href="/wiki/Evidence-based_nursing" title="Evidence-based nursing">Evidence-based nursing</a></li> <li><a href="/wiki/Evidence-based_pharmacy_in_developing_countries" title="Evidence-based pharmacy in developing countries">Evidence-based pharmacy in developing countries</a></li> <li><a href="/wiki/Evidence-based_policing" title="Evidence-based policing">Evidence-based policing</a></li> <li><a href="/wiki/Evidence-based_prosecution" title="Evidence-based prosecution">Evidence-based prosecution</a></li> <li><a href="/wiki/Evidence-based_policy" title="Evidence-based policy">Evidence-based policy</a></li> <li><a href="/wiki/Evidence-based_scheduling" title="Evidence-based scheduling">Evidence-based scheduling</a></li> <li><a href="/wiki/Evidence-based_toxicology" title="Evidence-based toxicology">Evidence-based toxicology</a></li> <li><a href="/wiki/Journalology" title="Journalology">Journalology</a></li> <li><a href="/wiki/Metascience" title="Metascience">Metascience</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Clinical_study_design" title="Clinical study design">Methods</a> and concepts</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Clinical_trial" title="Clinical trial">Clinical trial</a></li> <li><a href="/wiki/Systematic_review" title="Systematic review">Systematic review</a></li> <li><a href="/wiki/Meta-analysis" title="Meta-analysis">Meta-analysis</a></li> <li><a href="/wiki/Umbrella_review" title="Umbrella review">Umbrella review</a></li> <li><a href="/wiki/Randomized_controlled_trial" title="Randomized controlled trial">Randomized controlled trial</a></li> <li><a href="/wiki/Health_technology_assessment" title="Health technology assessment">Health technology assessment</a></li> <li><a href="/wiki/PICO_process" title="PICO process">PICO process</a></li> <li><a href="/wiki/GRADE_approach" title="GRADE approach">GRADE approach</a></li> <li><a href="/wiki/Pragmatic_clinical_trial" title="Pragmatic clinical trial">Pragmatic clinical trial</a></li> <li><a href="/wiki/Spaced_repetition" title="Spaced repetition">Spaced repetition</a></li> <li><a href="/wiki/Risk_assessment" title="Risk assessment">Risk assessment</a></li> <li>Scientific <a href="/wiki/Uncertainty" title="Uncertainty">uncertainty</a></li> <li><a href="/wiki/Policy-based_evidence_making" title="Policy-based evidence making">Policy-based evidence making</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">People</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Archie_Cochrane" title="Archie Cochrane">Archie Cochrane</a></li> <li><a href="/wiki/David_Sackett" title="David Sackett">David Sackett</a></li> <li><a href="/wiki/Iain_Chalmers" title="Iain Chalmers">Iain Chalmers</a></li> <li><a href="/wiki/Ken_Harvey_(professor)" title="Ken Harvey (professor)">Ken Harvey</a></li> <li><a href="/wiki/John_Ioannidis" title="John Ioannidis">John Ioannidis</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Groups</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%">Non-profit</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/James_Lind_Alliance" title="James Lind Alliance">James Lind Alliance</a></li> <li><a href="/wiki/Cochrane_(organisation)" title="Cochrane (organisation)">Cochrane Collaboration</a></li> <li><a href="/wiki/Campbell_Collaboration" title="Campbell Collaboration">Campbell Collaboration</a></li> <li><a href="/wiki/Science-Based_Medicine" title="Science-Based Medicine">Science-Based Medicine</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Governmental</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Agency_for_Healthcare_Research_and_Quality" title="Agency for Healthcare Research and Quality">Agency for Healthcare Research and Quality (AHRQ)</a></li> <li><a href="/wiki/Canadian_Agency_for_Drugs_and_Technologies_in_Health" class="mw-redirect" title="Canadian Agency for Drugs and Technologies in Health">Canadian Agency for Drugs and Technologies in Health (CADTH)</a></li> <li><a href="/wiki/European_Network_for_Health_Technology_Assessment" title="European Network for Health Technology Assessment">EUnetHTA</a></li> <li><a href="/wiki/German_Agency_for_Quality_in_Medicine" title="German Agency for Quality in Medicine">German Agency for Quality in Medicine (AEZQ)</a></li> <li><a href="/wiki/National_Institute_for_Health_and_Care_Excellence" title="National Institute for Health and Care Excellence">National Institute for Health and Care Excellence (NICE)</a></li> <li><a href="/wiki/Swedish_Agency_for_Health_Technology_Assessment_and_Assessment_of_Social_Services" title="Swedish Agency for Health Technology Assessment and Assessment of Social Services">Swedish Agency for Health Technology Assessment and Assessment of Social Services (SBU)</a></li> <li><a href="/wiki/Evidence-Informed_Policy_Network" title="Evidence-Informed Policy Network">WHO Evidence-Informed Policy Network (EVIPNet)</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Academic</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Centre_for_Reviews_and_Dissemination" title="Centre for Reviews and Dissemination">Centre for Reviews and Dissemination</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Other</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Examine.com" title="Examine.com">Examine.com</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr></tbody></table></div> <p><span class="noviewer" typeof="mw:File"><span><img alt="Public Domain" src="//upload.wikimedia.org/wikipedia/en/thumb/6/62/PD-icon.svg/12px-PD-icon.svg.png" decoding="async" width="12" height="12" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/6/62/PD-icon.svg/18px-PD-icon.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/6/62/PD-icon.svg/24px-PD-icon.svg.png 2x" data-file-width="196" data-file-height="196" /></span></span> This article incorporates <a href="/wiki/Copyright_status_of_works_by_the_federal_government_of_the_United_States" title="Copyright status of works by the federal government of the United States">public domain material</a> from <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation cs1"><a rel="nofollow" class="external text" href="https://www.cancer.gov/dictionary"><i>Dictionary of Cancer Terms</i></a>. <a href="/wiki/U.S._National_Cancer_Institute" class="mw-redirect" title="U.S. National Cancer Institute">U.S. National Cancer Institute</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Dictionary+of+Cancer+Terms&rft.pub=U.S.+National+Cancer+Institute&rft_id=http%3A%2F%2Fwww.cancer.gov%2Fdictionary&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHierarchy+of+evidence" class="Z3988"></span> </p>    </div><noscript><img src="https://login.wikimedia.org/wiki/Special:CentralAutoLogin/start?type=1x1" alt="" width="1" height="1" style="border: none; position: absolute;"></noscript> <div class="printfooter" data-nosnippet="">Retrieved from "<a dir="ltr" href="https://en.wikipedia.org/w/index.php?title=Hierarchy_of_evidence&oldid=1243995306">https://en.wikipedia.org/w/index.php?title=Hierarchy_of_evidence&oldid=1243995306</a>"</div></div> <div id="catlinks" class="catlinks" data-mw="interface"><div id="mw-normal-catlinks" class="mw-normal-catlinks"><a href="/wiki/Help:Category" title="Help:Category">Categories</a>: <ul><li><a href="/wiki/Category:Evidence" title="Category:Evidence">Evidence</a></li><li><a href="/wiki/Category:Evidence-based_practices" title="Category:Evidence-based practices">Evidence-based practices</a></li><li><a href="/wiki/Category:Research" title="Category:Research">Research</a></li><li><a href="/wiki/Category:Clinical_research" title="Category:Clinical research">Clinical research</a></li></ul></div><div id="mw-hidden-catlinks" class="mw-hidden-catlinks mw-hidden-cats-hidden">Hidden categories: <ul><li><a href="/wiki/Category:All_articles_with_dead_external_links" title="Category:All articles with dead external links">All articles with dead external links</a></li><li><a href="/wiki/Category:Articles_with_dead_external_links_from_September_2017" title="Category:Articles with dead external links from September 2017">Articles with dead external links from September 2017</a></li><li><a href="/wiki/Category:Articles_with_permanently_dead_external_links" title="Category:Articles with permanently dead external links">Articles with permanently dead external links</a></li><li><a href="/wiki/Category:Articles_with_short_description" title="Category:Articles with short description">Articles with short description</a></li><li><a href="/wiki/Category:Short_description_matches_Wikidata" title="Category:Short description matches Wikidata">Short description matches Wikidata</a></li><li><a href="/wiki/Category:All_articles_with_unsourced_statements" title="Category:All articles with unsourced statements">All articles with unsourced statements</a></li><li><a href="/wiki/Category:Articles_with_unsourced_statements_from_November_2023" title="Category:Articles with unsourced statements from November 2023">Articles with unsourced statements from November 2023</a></li><li><a href="/wiki/Category:Wikipedia_articles_needing_clarification_from_March_2018" title="Category:Wikipedia articles needing clarification from March 2018">Wikipedia articles needing clarification from March 2018</a></li><li><a href="/wiki/Category:Wikipedia_articles_incorporating_text_from_the_National_Cancer_Institute_Dictionary_of_Cancer_Terms" title="Category:Wikipedia articles incorporating text from the National Cancer Institute Dictionary of Cancer Terms">Wikipedia articles incorporating text from the National Cancer Institute Dictionary of Cancer Terms</a></li></ul></div></div> </div> </main> </div> <div class="mw-footer-container"> <footer id="footer" class="mw-footer" > <ul id="footer-info"> <li id="footer-info-lastmod"> This page was last edited on 4 September 2024, at 14:05<span class="anonymous-show"> (UTC)</span>.</li> <li id="footer-info-copyright">Text is available under the <a href="/wiki/Wikipedia:Text_of_the_Creative_Commons_Attribution-ShareAlike_4.0_International_License" title="Wikipedia:Text of the Creative Commons Attribution-ShareAlike 4.0 International License">Creative Commons Attribution-ShareAlike 4.0 License</a>; additional terms may apply. By using this site, you agree to the <a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Terms_of_Use" class="extiw" title="foundation:Special:MyLanguage/Policy:Terms of Use">Terms of Use</a> and <a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy" class="extiw" title="foundation:Special:MyLanguage/Policy:Privacy policy">Privacy Policy</a>. Wikipedia® is a registered trademark of the <a rel="nofollow" class="external text" href="https://wikimediafoundation.org/">Wikimedia Foundation, Inc.</a>, a non-profit organization.</li> </ul> <ul id="footer-places"> <li id="footer-places-privacy"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy">Privacy policy</a></li> <li id="footer-places-about"><a href="/wiki/Wikipedia:About">About Wikipedia</a></li> <li id="footer-places-disclaimers"><a href="/wiki/Wikipedia:General_disclaimer">Disclaimers</a></li> <li id="footer-places-contact"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us">Contact Wikipedia</a></li> <li id="footer-places-wm-codeofconduct"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Universal_Code_of_Conduct">Code of Conduct</a></li> <li id="footer-places-developers"><a href="https://developer.wikimedia.org">Developers</a></li> <li id="footer-places-statslink"><a href="https://stats.wikimedia.org/#/en.wikipedia.org">Statistics</a></li> <li id="footer-places-cookiestatement"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Cookie_statement">Cookie statement</a></li> <li id="footer-places-mobileview"><a href="//en.m.wikipedia.org/w/index.php?title=Hierarchy_of_evidence&mobileaction=toggle_view_mobile" class="noprint stopMobileRedirectToggle">Mobile view</a></li> </ul> <ul id="footer-icons" class="noprint"> <li id="footer-copyrightico"><a href="https://wikimediafoundation.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><img src="/static/images/footer/wikimedia-button.svg" width="84" height="29" alt="Wikimedia Foundation" loading="lazy"></a></li> <li id="footer-poweredbyico"><a href="https://www.mediawiki.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><img src="/w/resources/assets/poweredby_mediawiki.svg" alt="Powered by MediaWiki" width="88" height="31" loading="lazy"></a></li> </ul> </footer> </div> </div> </div> <div class="vector-settings" id="p-dock-bottom"> <ul></ul> </div><script>(RLQ=window.RLQ||[]).push(function(){mw.config.set({"wgHostname":"mw-web.codfw.main-6b7f745dd4-ctqwl","wgBackendResponseTime":179,"wgPageParseReport":{"limitreport":{"cputime":"0.754","walltime":"0.883","ppvisitednodes":{"value":4623,"limit":1000000},"postexpandincludesize":{"value":144757,"limit":2097152},"templateargumentsize":{"value":4566,"limit":2097152},"expansiondepth":{"value":17,"limit":100},"expensivefunctioncount":{"value":7,"limit":500},"unstrip-depth":{"value":1,"limit":20},"unstrip-size":{"value":187187,"limit":5000000},"entityaccesscount":{"value":0,"limit":400},"timingprofile":["100.00% 808.128 1 -total"," 43.57% 352.085 1 Template:Reflist"," 21.95% 177.399 28 Template:Cite_journal"," 11.13% 89.940 1 Template:Evidence-based_practices"," 10.84% 87.577 1 Template:Short_description"," 10.83% 87.495 1 Template:Sidebar"," 9.38% 75.786 1 Template:Cite_news"," 5.63% 45.490 4 Template:Fix"," 5.59% 45.148 1 Template:Sfn"," 5.47% 44.192 2 Template:Cn"]},"scribunto":{"limitreport-timeusage":{"value":"0.508","limit":"10.000"},"limitreport-memusage":{"value":9261251,"limit":52428800},"limitreport-logs":"anchor_id_list = table#1 {\n [\"CITEREFAtkinsBestBrissEccles2004\"] = 1,\n [\"CITEREFBalshemHelfandSchünemannOxman2011\"] = 1,\n [\"CITEREFBluhm2011\"] = 1,\n [\"CITEREFBlunt2015\"] = 1,\n [\"CITEREFBorgerson2009\"] = 1,\n [\"CITEREFBurns_el_al2011\"] = 1,\n [\"CITEREFCanadian_Task_Force_on_the_Periodic_Health_Examination1979\"] = 1,\n [\"CITEREFCanadian_Task_Force_on_the_Periodic_Health_Examination1984\"] = 1,\n [\"CITEREFCanadian_Task_Force_on_the_Periodic_Health_Examination1986\"] = 1,\n [\"CITEREFCanadian_Task_Force_on_the_Periodic_Health_Examination1988\"] = 1,\n [\"CITEREFCartwright2007\"] = 1,\n [\"CITEREFConcato2004\"] = 1,\n [\"CITEREFGolderLokeBland2011\"] = 1,\n [\"CITEREFGreenhalgh1997\"] = 1,\n [\"CITEREFGugiu,_PCWestine,_CDCoryn,_CLHobson,_KA2012\"] = 1,\n [\"CITEREFGuyattSackettSinclairHayward1995\"] = 1,\n [\"CITEREFHadornBakerHodgesHicks1996\"] = 1,\n [\"CITEREFJeremy_Howick2011\"] = 1,\n [\"CITEREFLa_Caze2011\"] = 1,\n [\"CITEREFLimVosFlaxmanDanaei2012\"] = 1,\n [\"CITEREFNational_Cancer_Instituten.d.\"] = 1,\n [\"CITEREFOCEBM_Levels_of_Evidence_Working_Group2016\"] = 1,\n [\"CITEREFPaulGalliniArchier2012\"] = 1,\n [\"CITEREFRawlins2008\"] = 1,\n [\"CITEREFReed_Siemieniuk_and_Gordon_Guyatt\"] = 1,\n [\"CITEREFSchünemannBestVistOxman2003\"] = 1,\n [\"CITEREFShafeeMasukumeKipersztokDas2017\"] = 1,\n [\"CITEREFSiegfried2017\"] = 1,\n [\"CITEREFSolomon2011\"] = 1,\n [\"CITEREFStegenga2011\"] = 1,\n [\"CITEREFStegenga2014\"] = 1,\n [\"CITEREFStrausRichardsonGlasziouHaynes2005\"] = 1,\n [\"CITEREFU.S._Preventive_Services_Task_Force1989\"] = 1,\n [\"CITEREFUpshur2005\"] = 1,\n [\"CITEREFWelsh2010\"] = 1,\n [\"CITEREFWilson1995\"] = 1,\n [\"CITEREFWorrall2002\"] = 1,\n}\ntemplate_list = table#1 {\n [\"!\"] = 4,\n [\"Cite book\"] = 3,\n [\"Cite journal\"] = 28,\n [\"Cite news\"] = 1,\n [\"Cite thesis\"] = 1,\n [\"Cite web\"] = 9,\n [\"Clarify\"] = 1,\n [\"Cn\"] = 2,\n [\"Dead link\"] = 2,\n [\"Evidence-based practice\"] = 1,\n [\"Evidence-based practices\"] = 1,\n [\"Harvid\"] = 1,\n [\"Main\"] = 1,\n [\"Multiple image\"] = 1,\n [\"NCI-cancer-dict\"] = 1,\n [\"Portal\"] = 1,\n [\"Refbegin\"] = 1,\n [\"Refend\"] = 1,\n [\"Reflist\"] = 1,\n [\"Rp\"] = 3,\n [\"Sfn\"] = 1,\n [\"Short description\"] = 1,\n}\narticle_whitelist = table#1 {\n}\n"},"cachereport":{"origin":"mw-web.codfw.main-6b7f745dd4-8mfqd","timestamp":"20241125133914","ttl":2592000,"transientcontent":false}}});});</script> <script type="application/ld+json">{"@context":"https:\/\/schema.org","@type":"Article","name":"Hierarchy of evidence","url":"https:\/\/en.wikipedia.org\/wiki\/Hierarchy_of_evidence","sameAs":"http:\/\/www.wikidata.org\/entity\/Q17135794","mainEntity":"http:\/\/www.wikidata.org\/entity\/Q17135794","author":{"@type":"Organization","name":"Contributors to Wikimedia projects"},"publisher":{"@type":"Organization","name":"Wikimedia Foundation, Inc.","logo":{"@type":"ImageObject","url":"https:\/\/www.wikimedia.org\/static\/images\/wmf-hor-googpub.png"}},"datePublished":"2006-03-26T10:57:33Z","dateModified":"2024-09-04T14:05:02Z","headline":"heuristic ranking science research results"}</script> </body> </html>