value of flow diagrams in reports of randomized controlled trials context diagrams of the flow of participants through a clinical trial are recommended in the consolidated standards for reporting of trials consort statement but it is unclear whether such flow diagrams improve the quality of trial reportsobjective to examine the information contributed by flow diagrams and the completeness of reporting overall in reports of randomized controlled trials rcts published in 5 general and internal medicine journalsdesign and setting analysis of 270 reports of rcts published in 1998 in the annals of internal medicine aim n 19 bmj n 42 jama n 45 the lancet n 81 and the new england journal of medicine nejm n 83main outcome measures proportion of reports that included a flow diagram information provided in flow diagrams and completeness of reporting about flow of participants overall in flow diagrams or textresults a total of 139 reports 515 of rcts included a flow diagram but this varied widely among journals aim 210 bmj 381 jama 800 the lancet 938 and nejm 84 diagrams generally provided useful information but only 73 525 included the number of participants who received allocated interventions and only 32 230 included the number of participants included in the analysis in logistic regression analysis overall completeness of reporting about flow of study participants was associated with publication of a flow diagramconclusions flow diagrams are associated with improved quality of reporting of randomized controlled trials however the structure of current flow diagrams is less than ideal we propose a revised flow diagram that includes all important counts through the stages of parallel group trials