{"id":1866,"date":"2021-06-10T13:01:00","date_gmt":"2021-06-10T12:01:00","guid":{"rendered":"https:\/\/www.psyctc.org\/psyctc\/?post_type=docs&#038;p=1866"},"modified":"2021-11-10T19:26:41","modified_gmt":"2021-11-10T19:26:41","password":"","slug":"ceiling-effect","status":"publish","type":"docs","link":"https:\/\/www.psyctc.org\/psyctc\/glossary2\/ceiling-effect\/","title":{"rendered":"Ceiling effect"},"content":{"rendered":"\n<figure class=\"wp-block-table\"><table><tbody><tr><td>In OM this refers to most people choosing the maximum possible score on an item or a scale. This leaves no scope to record differences above this ceiling. A floor effect is the opposite: most or all people scoring on the lowest possible score. Both limit the Variance of scores.<br>A ceiling effect can make an item, or, much more seriously, a whole OM score insensitive to differences and change above the \u201cceiling\u201d so an item like \u201cI have felt unhappy\u201d may be fine to detect differences in general well-being but won\u2019t distinguish between those with mild low mood and those in a deeply despairing state.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h4 class=\"wp-block-heading\">Detail<\/h4>\n\n\n\n<p>Bit more about diagnosing it, impact and about IRT?<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Try also &#8230;<\/h4>\n\n\n\n<p><a href=\"https:\/\/www.psyctc.org\/psyctc\/glossary2\/floor-and-ceiling-effects\/\" data-type=\"docs\" data-id=\"1871\">Floor effect<\/a><br><a href=\"https:\/\/www.psyctc.org\/psyctc\/glossary2\/variance\/\" data-type=\"docs\" data-id=\"2435\">Variance<\/a><br><a href=\"https:\/\/www.psyctc.org\/psyctc\/glossary2\/range\/\" data-type=\"docs\" data-id=\"2130\">Range<\/a><br>Range constriction<br><a href=\"https:\/\/www.psyctc.org\/psyctc\/glossary2\/bias\/\" data-type=\"docs\" data-id=\"1845\">Bias<\/a><br>Validity &amp; invalidity<br>Item Response Theory<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Chapters<\/h4>\n\n\n\n<p>Nothing here yet!<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Further reading<\/h4>\n\n\n\n<p>Nothing here yet!<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Online tools<\/h4>\n\n\n\n<p>Possible simulation and perhaps diagnostics for ceiling and floor effects.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>In OM this refers to most people choosing the maximum possible score on an item or a scale. This leaves no scope to record differences above this ceiling. A floor effect is the opposite: most or all people scoring on the lowest possible score. Both limit the Variance of scores.A ceiling effect can make an &hellip; <a href=\"https:\/\/www.psyctc.org\/psyctc\/glossary2\/ceiling-effect\/\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">Ceiling effect<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","template":"","meta":{"footnotes":""},"doc_category":[18],"glossaries":[],"doc_tag":[],"knowledge_base":[],"class_list":["post-1866","docs","type-docs","status-publish","hentry","doc_category-om-book"],"year_month":"2026-05","word_count":147,"total_views":"1354","reactions":{"happy":"0","normal":"0","sad":"0"},"author_info":{"name":"chris","author_nicename":"chris","author_url":"https:\/\/www.psyctc.org\/psyctc\/author\/chris\/"},"doc_category_info":[{"term_name":"All OM book glossary entries","term_url":"https:\/\/www.psyctc.org\/psyctc\/glossary\/non-knowledgebase\/om-book\/"}],"doc_tag_info":[],"knowledge_base_info":[],"knowledge_base_slug":[],"_links":{"self":[{"href":"https:\/\/www.psyctc.org\/psyctc\/wp-json\/wp\/v2\/docs\/1866","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.psyctc.org\/psyctc\/wp-json\/wp\/v2\/docs"}],"about":[{"href":"https:\/\/www.psyctc.org\/psyctc\/wp-json\/wp\/v2\/types\/docs"}],"author":[{"embeddable":true,"href":"https:\/\/www.psyctc.org\/psyctc\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.psyctc.org\/psyctc\/wp-json\/wp\/v2\/comments?post=1866"}],"version-history":[{"count":2,"href":"https:\/\/www.psyctc.org\/psyctc\/wp-json\/wp\/v2\/docs\/1866\/revisions"}],"predecessor-version":[{"id":2540,"href":"https:\/\/www.psyctc.org\/psyctc\/wp-json\/wp\/v2\/docs\/1866\/revisions\/2540"}],"wp:attachment":[{"href":"https:\/\/www.psyctc.org\/psyctc\/wp-json\/wp\/v2\/media?parent=1866"}],"wp:term":[{"taxonomy":"doc_category","embeddable":true,"href":"https:\/\/www.psyctc.org\/psyctc\/wp-json\/wp\/v2\/doc_category?post=1866"},{"taxonomy":"glossaries","embeddable":true,"href":"https:\/\/www.psyctc.org\/psyctc\/wp-json\/wp\/v2\/glossaries?post=1866"},{"taxonomy":"doc_tag","embeddable":true,"href":"https:\/\/www.psyctc.org\/psyctc\/wp-json\/wp\/v2\/doc_tag?post=1866"},{"taxonomy":"knowledge_base","embeddable":true,"href":"https:\/\/www.psyctc.org\/psyctc\/wp-json\/wp\/v2\/knowledge_base?post=1866"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}