[Comparison of pragmatic clinical trials and explanatory clinical trials].

Clinical trials are often designed as either pragmatic or explanatory. The pragmatic clinical trials are generally used for measuring the effectiveness of a treatment in common clinical practice, while the explanatory trial for measuring the efficacy of a treatment under ideal conditions. Since the methods concerning pragmatic clinical trials are less introduced in China, its archetypal features, advantages and limitations were introduced in this paper. And a current study of pragmatic clinical trials on using acpuncture for treatment of low back pain carried out in German was taken as an example to illustrate the practical methods concretely. The key steps of the design were presented in detail, and reasonable suggestions about the problems often encountered in the trial, as well as how to balance the internal and external validity, outcome measurement, etc., were offered.