BMJ CONSORT and Pragmatic Trials in Healthcare ( Practihc ) groups

service Email alerting box at the top left of the article Receive free email alerts when new articles cite this article-sign up in the Topic collections (3909 articles) Clinical trials (epidemiology) Articles on similar topics can be found in the following collections Notes To order reprints follow the "Request Permissions" link in the navigation box Randomised controlled trials are used to assess the ben‑ efits and harms of interventions in health care. If con‑ ducted properly, they minimise the risk of bias (threats to internal validity), particularly selection bias. There is, however, considerable evidence that trials are not always well reported, 3 4 and this can be associated with bias, such as selective reporting of outcomes. 5 The usefulness of a trial report also depends on the clarity with which it details the relevance of its interven‑ tions, participants, outcomes, and design to the clinical, health service, or policy question it examines. Further‑ more, a trial may be valid and useful in the healthcare setting in which it was conducted but have limited appli‑ cability (also known as generalisability or external valid‑ ity) beyond this because of differences between the trial setting and other settings to which its results are to be extrapolated. Schwartz and Lellouch 6 coined the terms " pragmatic " to describe trials designed to help choose between options for care, and " explanatory " to describe trials designed to test causal research hypotheses—for exam‑ ple, that an intervention causes a particular biological Pragmatic trials are designed to inform decisions about practice, but poor reporting can reduce their usefulness. The consort and practihc groups describe modifications to the CONSORT guidelines to help readers assess the applicability of the results table 1 | Key differences between trials with explanatory and pragmatic attitudes, adapted from a table presented at the 2008 Society for Clinical Trials meeting by Question Efficacy—can the intervention work? Effectiveness—does the intervention work when used in normal practice? Setting Well resourced, " ideal " setting Normal practice Participants Highly selected. Poorly adherent participants and those with conditions which might dilute the effect are often excluded Little or no selection beyond the clinical indication of interest Intervention Strictly enforced and adherence is monitored closely Applied flexibly as it would be in normal practice Outcomes Often short term surrogates or process measures Directly relevant to participants, funders, communities, and healthcare practitioners Relevance to practice Indirect—little effort made to …