{"id":1065,"date":"2015-03-31T20:10:12","date_gmt":"2015-03-31T19:10:12","guid":{"rendered":"http:\/\/stg-blogs.bmj.com\/adc\/?p=1065"},"modified":"2015-03-13T21:53:33","modified_gmt":"2015-03-13T20:53:33","slug":"statsminiblog-recursive-partitioning","status":"publish","type":"post","link":"https:\/\/stg-blogs.bmj.com\/adc\/2015\/03\/31\/statsminiblog-recursive-partitioning\/","title":{"rendered":"StatsMiniBlog: Recursive partitioning"},"content":{"rendered":"<p><a href=\"https:\/\/stg-blogs.bmj.com\/adc\/files\/2014\/02\/20140205-091454.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-full wp-image-859\" src=\"https:\/\/stg-blogs.bmj.com\/adc\/files\/2014\/02\/20140205-091454.jpg\" alt=\"20140205-091454.jpg\" width=\"180\" height=\"76\" \/><\/a> If you want to know who does, and who does not, need a bone marrow biopsy to detect malignant infiltration if the patient has rhabdomyosarcoma, you might want to start by <a href=\"http:\/\/jco.ascopubs.org\/content\/early\/2013\/08\/12\/JCO.2012.44.6476.full.pdf\">taking a very large cohort of patients who had RMS <\/a>and had a load of tests, including marrows.\u00a0Then construct a decision tree that settles on\u00a0identifying\u00a0the group without marrow disease.<\/p>\n<p>One (very good) stats process to do this is called &#8216;recursive partitioning&#8217;. It does what it says &#8211; splits the group up (partitions) it and then splits those up (recursively) until you&#8217;ve got a &#8216;good enough&#8217; answer. Where the split is placed is by calculating and recalculating a threshold value, seeing how well that discriminates, and then moving on. For simple dichotomous measures this &#8216;threshold finding&#8217; is incredibly easy as there are only two categories&#8230;<\/p>\n<p>Now, h<a title=\"Springing into action\" href=\"https:\/\/stg-blogs.bmj.com\/adc\/2014\/04\/02\/springing-into-action\/\">ow you decide what &#8216;good enough&#8217; is is a matter of clinical judgemen<\/a>t (e.g. what % of BM +ve patients would you miss &#8211; 2%?), and that&#8217;s worth a few arguments.<\/p>\n<p>&#8211; Archi<!--TrendMD v2.4.8--><\/p>\n","protected":false},"excerpt":{"rendered":"<p>If you want to know who does, and who does not, need a bone marrow biopsy to detect malignant infiltration if the patient has rhabdomyosarcoma, you might want to start by taking a very large cohort of patients who had RMS and had a load of tests, including marrows.\u00a0Then construct a decision tree that settles [&#8230;]<\/p>\n<p><a class=\"btn btn-secondary understrap-read-more-link\" href=\"https:\/\/stg-blogs.bmj.com\/adc\/2015\/03\/31\/statsminiblog-recursive-partitioning\/\">Read More&#8230;<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[2676],"tags":[],"class_list":["post-1065","post","type-post","status-publish","format-standard","hentry","category-stats"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/stg-blogs.bmj.com\/adc\/wp-json\/wp\/v2\/posts\/1065","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/stg-blogs.bmj.com\/adc\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/stg-blogs.bmj.com\/adc\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/stg-blogs.bmj.com\/adc\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/stg-blogs.bmj.com\/adc\/wp-json\/wp\/v2\/comments?post=1065"}],"version-history":[{"count":0,"href":"https:\/\/stg-blogs.bmj.com\/adc\/wp-json\/wp\/v2\/posts\/1065\/revisions"}],"wp:attachment":[{"href":"https:\/\/stg-blogs.bmj.com\/adc\/wp-json\/wp\/v2\/media?parent=1065"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/stg-blogs.bmj.com\/adc\/wp-json\/wp\/v2\/categories?post=1065"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/stg-blogs.bmj.com\/adc\/wp-json\/wp\/v2\/tags?post=1065"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}