Pragmatic clinical trials.

Both pragmatic and explanatory randomised controlled trials have a useful role to play in the evaluation of health care interventions. In this descriptive article, the key steps in conducting a pragmatic trial are described. The strengths and limitations of pragmatic trials are also discussed. The main strength of pragmatic trials is that they can evaluate a therapy as it is used in normal practice. Comparisons are made between pragmatic and explanatory trials, on the understanding that trials may have aspects to them that make the trial more of a hybrid. A case is made for the appropriate use and relevance of pragmatic trials in the evaluation of alternative and complementary medicine.