{"id":847,"date":"2015-08-10T15:36:27","date_gmt":"2015-08-10T14:36:27","guid":{"rendered":"http:\/\/pcool.dyndns.org:8080\/statsbook\/?page_id=847"},"modified":"2025-06-30T23:11:44","modified_gmt":"2025-06-30T22:11:44","slug":"randomised-controlled-trial","status":"publish","type":"page","link":"https:\/\/pcool.dyndns.org\/index.php\/randomised-controlled-trial\/","title":{"rendered":"Randomised Controlled Trial"},"content":{"rendered":"\n<p><strong>Randomised Controlled Trial <\/strong><\/p>\n\n\n\n<p>The gold standard is the double blind randomised controlled trial. It has two arms: a study group and a control group. <a href=\"https:\/\/pcool.dyndns.org\/index.php\/bias-and-accuracy\/\" data-type=\"page\" data-id=\"838\">As discussed<\/a>, blinding is designed to reduce observational bias and randomisation to reduce selection bias.<\/p>\n\n\n\n<p><strong>The advantages of a randomised controlled trial are:<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Evaluation of single variable<\/li>\n\n\n\n<li>Prospective study<\/li>\n\n\n\n<li>Reduces bias<\/li>\n\n\n\n<li>Allows for meta-analysis by combining several randomised controlled trials<\/li>\n<\/ul>\n\n\n\n<p><strong>&nbsp;Steps in setting up Randomised Controlled Trial<\/strong><\/p>\n\n\n\n<p>The following steps are required in setting up a randomised controlled trial:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Hypothesis<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong><a href=\"https:\/\/pcool.dyndns.org\/index.php\/statistical-tests\/\" data-type=\"page\" data-id=\"602\">Null hypothesis<\/a><\/strong>: there is no difference as opposed to the alternate hypothesis (there is a difference)<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Inclusion \/ Exclusion Criteria<\/strong>\n<ul class=\"wp-block-list\">\n<li>Describe the criteria for exclusion and inclusion in the study<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Outcome Measure<\/strong>\n<ul class=\"wp-block-list\">\n<li>Select outcome measure and the <strong><a href=\"https:\/\/pcool.dyndns.org\/index.php\/data-types\/\" data-type=\"page\" data-id=\"355\">type of data<\/a><\/strong>. Data could be nominal, ordinal or continuous. Depending or the type of data, a <strong>test statistic<\/strong> is selected. If continuous data are normally distributed, <a href=\"https:\/\/pcool.dyndns.org\/index.php\/non-parametric-tests-2\/\" data-type=\"page\" data-id=\"605\">parametric statistics<\/a> (i.e. t-test) can be used. Alternatively, we can use a <a href=\"https:\/\/pcool.dyndns.org\/index.php\/non-parametric-tests\/\" data-type=\"page\" data-id=\"594\">non parametric statistical test<\/a>.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><a href=\"https:\/\/pcool.dyndns.org\/index.php\/bias-and-accuracy\/\" data-type=\"page\" data-id=\"838\"><strong>Bias<\/strong><\/a>\n<ul class=\"wp-block-list\">\n<li>Assessment of bias; there could be selection bias, confounding bias or observational bias. Selection bias is reduced by randomisation. If there is a known confounding factor, stratification can be used to reduce confounding bias. Observational bias is reduced by blinding.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong><a href=\"https:\/\/pcool.dyndns.org\/index.php\/power-analysis\/\" data-type=\"page\" data-id=\"597\">Power Analysis<\/a><\/strong>\n<ul class=\"wp-block-list\">\n<li>Power analysis is performed to estimate the number of patients required in the study. It is necessary to have an estimate of:\n<ul class=\"wp-block-list\">\n<li><strong>Difference desired to detect<\/strong><\/li>\n\n\n\n<li><strong>Spread of data<\/strong> (variance \/ standard deviation)<\/li>\n\n\n\n<li><strong>Significance level (\u03b1)<\/strong> (<a href=\"https:\/\/pcool.dyndns.org\/index.php\/errors\/\" data-type=\"page\" data-id=\"816\">type 1 error<\/a>)<\/li>\n\n\n\n<li><strong>Power<\/strong> (<a href=\"https:\/\/pcool.dyndns.org\/index.php\/errors\/\" data-type=\"page\" data-id=\"816\">type 2 error<\/a>)<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li>A pilot study might be required to estimate these parameters.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Ethical Approval<\/strong><\/li>\n\n\n\n<li><strong>Informed Consent<\/strong><\/li>\n\n\n\n<li><strong>Collection of Data &amp; Results<\/strong><\/li>\n\n\n\n<li><a href=\"https:\/\/pcool.dyndns.org\/index.php\/statistical-tests\/\" data-type=\"page\" data-id=\"602\"><strong>Analysis<\/strong><\/a>\n<ul class=\"wp-block-list\">\n<li>Use parametric or non parametric tests as appropriate. Usually computers (R or Python) are used in the analysis.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Conclusions<\/strong><\/li>\n\n\n\n<li><strong>Publication and Presentation of Data<\/strong><\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"<p>Randomised Controlled Trial The gold standard is the double blind randomised controlled trial. It has two arms: a study group and a control group. As discussed, blinding is designed to reduce observational bias and randomisation to reduce selection bias. The advantages of a randomised controlled trial are: &nbsp;Steps in setting up Randomised Controlled Trial The [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"inline_featured_image":false,"footnotes":""},"class_list":["post-847","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/pcool.dyndns.org\/index.php\/wp-json\/wp\/v2\/pages\/847","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pcool.dyndns.org\/index.php\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/pcool.dyndns.org\/index.php\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/pcool.dyndns.org\/index.php\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/pcool.dyndns.org\/index.php\/wp-json\/wp\/v2\/comments?post=847"}],"version-history":[{"count":1,"href":"https:\/\/pcool.dyndns.org\/index.php\/wp-json\/wp\/v2\/pages\/847\/revisions"}],"predecessor-version":[{"id":4634,"href":"https:\/\/pcool.dyndns.org\/index.php\/wp-json\/wp\/v2\/pages\/847\/revisions\/4634"}],"wp:attachment":[{"href":"https:\/\/pcool.dyndns.org\/index.php\/wp-json\/wp\/v2\/media?parent=847"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}