{"id":1141,"date":"2015-08-14T21:03:41","date_gmt":"2015-08-14T20:03:41","guid":{"rendered":"https:\/\/blogs.bmj.com\/adc\/?p=1141"},"modified":"2015-07-22T16:20:06","modified_gmt":"2015-07-22T15:20:06","slug":"statsminiblog-calibration-vs-discrimination","status":"publish","type":"post","link":"https:\/\/blogs.bmj.com\/adc\/2015\/08\/14\/statsminiblog-calibration-vs-discrimination\/","title":{"rendered":"StatsMiniBlog: Calibration vs Discrimination"},"content":{"rendered":"<p><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-full wp-image-859\" src=\"https:\/\/blogs.bmj.com\/adc\/files\/2014\/02\/20140205-091454.jpg\" alt=\"20140205-091454.jpg\" width=\"180\" height=\"76\" \/>There are a variety of clinical prediction rules in the world. If\u00a0you&#8217;ve seen one &#8211;\u00a0they always used to have a nomogram attached &#8211; it would take the answers to a few questions and come up with a &#8216;probability of bad thing happening&#8217;.<\/p>\n<p>As <a href=\"https:\/\/blogs.bmj.com\/adc\/2015\/04\/24\/predicting-ivig-resistance\/\">we&#8217;ve mentioned previously<\/a>, there&#8217;s an issue with deriving models\u00a0and assuming they will\u00a0work as well in every other place you try them (and have a read <a href=\"http:\/\/ep.bmj.com\/content\/95\/3\/83.extract\">here <\/a>and <a href=\"http:\/\/ep.bmj.com\/content\/95\/3\/88.abstract\">here <\/a>if you want a fuller explanation\u00a0from the E&amp;P section). A new model needs to be &#8216;validated&#8217; &#8211; that is, checked to see if it works.<\/p>\n<p>Two bits could\u00a0be looked at:<\/p>\n<p>a) Calibration &#8211; does the &#8216;predicted probability&#8217; from the model match(~ish) the observed probability in the new set<\/p>\n<p>b) Discrimination &#8211; if you set a threshold (say, less than 10% chance = low risk), does the model have the same sort of <a href=\"https:\/\/blogs.bmj.com\/adc\/2014\/03\/09\/sensitivity-and-specificity\/\">sensitivity and specificity<\/a> as the original data?<\/p>\n<p><a href=\"https:\/\/blogs.bmj.com\/adc\/2010\/06\/06\/its-how-ineffective\/\">How close<\/a> you need these to be to claim effective validation is, as many things, <a href=\"https:\/\/blogs.bmj.com\/adc\/2014\/04\/02\/springing-into-action\/\">a matter of clinical judgement<\/a> but it&#8217;s worth understanding what they are validating to make a sensible assessment.<\/p>\n<p>&#8211; Archi<!--TrendMD v2.4.8--><\/p>\n","protected":false},"excerpt":{"rendered":"<p>There are a variety of clinical prediction rules in the world. If\u00a0you&#8217;ve seen one &#8211;\u00a0they always used to have a nomogram attached &#8211; it would take the answers to a few questions and come up with a &#8216;probability of bad thing happening&#8217;. As we&#8217;ve mentioned previously, there&#8217;s an issue with deriving models\u00a0and assuming they will\u00a0work [&#8230;]<\/p>\n<p><a class=\"btn btn-secondary understrap-read-more-link\" href=\"https:\/\/blogs.bmj.com\/adc\/2015\/08\/14\/statsminiblog-calibration-vs-discrimination\/\">Read More&#8230;<\/a><\/p>\n","protected":false},"author":7,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2676],"tags":[],"class_list":["post-1141","post","type-post","status-publish","format-standard","hentry","category-stats"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.4 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>StatsMiniBlog: Calibration vs Discrimination - ADC Online Blog<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/blogs.bmj.com\/adc\/2015\/08\/14\/statsminiblog-calibration-vs-discrimination\/\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"StatsMiniBlog: Calibration vs Discrimination - ADC Online Blog\" \/>\n<meta property=\"og:description\" content=\"There are a variety of clinical prediction rules in the world. If\u00a0you&#8217;ve seen one &#8211;\u00a0they always used to have a nomogram attached &#8211; it would take the answers to a few questions and come up with a &#8216;probability of bad thing happening&#8217;. As we&#8217;ve mentioned previously, there&#8217;s an issue with deriving models\u00a0and assuming they will\u00a0work [...]Read More...\" \/>\n<meta property=\"og:url\" content=\"https:\/\/blogs.bmj.com\/adc\/2015\/08\/14\/statsminiblog-calibration-vs-discrimination\/\" \/>\n<meta property=\"og:site_name\" content=\"ADC Online Blog\" \/>\n<meta property=\"article:published_time\" content=\"2015-08-14T20:03:41+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/blogs.bmj.com\/adc\/files\/2014\/02\/20140205-091454.jpg\" \/>\n<meta name=\"author\" content=\"Bob Phillips\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Bob Phillips\" \/>\n\t<meta name=\"twitter:label2\" content=\"Estimated reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"1 minute\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\\\/\\\/blogs.bmj.com\\\/adc\\\/2015\\\/08\\\/14\\\/statsminiblog-calibration-vs-discrimination\\\/#article\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/blogs.bmj.com\\\/adc\\\/2015\\\/08\\\/14\\\/statsminiblog-calibration-vs-discrimination\\\/\"},\"author\":{\"name\":\"Bob Phillips\",\"@id\":\"https:\\\/\\\/blogs.bmj.com\\\/adc\\\/#\\\/schema\\\/person\\\/9e94029681ecf36e73bbd1eb2be2ef94\"},\"headline\":\"StatsMiniBlog: Calibration vs Discrimination\",\"datePublished\":\"2015-08-14T20:03:41+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\\\/\\\/blogs.bmj.com\\\/adc\\\/2015\\\/08\\\/14\\\/statsminiblog-calibration-vs-discrimination\\\/\"},\"wordCount\":200,\"commentCount\":0,\"publisher\":{\"@id\":\"https:\\\/\\\/blogs.bmj.com\\\/adc\\\/#organization\"},\"image\":{\"@id\":\"https:\\\/\\\/blogs.bmj.com\\\/adc\\\/2015\\\/08\\\/14\\\/statsminiblog-calibration-vs-discrimination\\\/#primaryimage\"},\"thumbnailUrl\":\"https:\\\/\\\/blogs.bmj.com\\\/adc\\\/files\\\/2014\\\/02\\\/20140205-091454.jpg\",\"articleSection\":[\"stats\"],\"inLanguage\":\"en-GB\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\\\/\\\/blogs.bmj.com\\\/adc\\\/2015\\\/08\\\/14\\\/statsminiblog-calibration-vs-discrimination\\\/#respond\"]}]},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/blogs.bmj.com\\\/adc\\\/2015\\\/08\\\/14\\\/statsminiblog-calibration-vs-discrimination\\\/\",\"url\":\"https:\\\/\\\/blogs.bmj.com\\\/adc\\\/2015\\\/08\\\/14\\\/statsminiblog-calibration-vs-discrimination\\\/\",\"name\":\"StatsMiniBlog: Calibration vs Discrimination - 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