ABSTRACT
Physicians refer to the medical literature for the most current information about how to treat their patients. How useful and reliable is the information they find? One difficulty is that the number of clinical trials, and the wide range of journals in which they are published, means that most physicians will be seeing only a portion of the reports-and that portion is usually a biased selection, because the most prominent journals often prefer the earliest or most statistically significant results. The individual clinical trials and their reports are also often defective in various ways, such as inadequate sample size, exclusion of randomized patients, and multiple testing. Conclusions of individual trials may conflict, making it unclear what to believe.
