Review articles in medical journals summarize large amounts of information on a particular topic; they are therefore a useful and popular source of information for doctors. However, some review articles reflect the personal opinions of the author more than the body of knowledge about a topic. Experts have proposed guidelines for how authors should write review articles in order to avoid personal bias. These guidelines recommend that authors should address a focused question, describe how they searched for and evaluated information, identify gaps in knowledge, and estimate risks and benefits of recommended treatments. Although studies have shown that the guidelines are reliable indicators of the quality of a review article, we do not know how widely authors of review articles actually follow those guidelines.