GUIDES FOR READING AND INTERPRETING SYSTEMATIC REVIEWS - II - HOW DIDTHE AUTHORS FIND THE STUDIES AND ASSESS THEIR QUALITY

One of the most powerful arguments used by the supporters of systemati c reviews is that they overcome most of the limitations of narrative r eviews by being the product of a scientific process to reduce bias and imprecision and by providing detailed information to allow replicatio n by others.(1,2) Two of the most effective mechanisms for a systemati c review to reduce bias and imprecision are including the maximum poss ible number of relevant individual trials and providing a detailed des cription of their strengths and limitations. We have structured this a rticle to serve 2 purposes. First, we describe the characteristics of the ideal search, the limitations and decisions that most reviewers fa ce when deciding how to search the literature, and the aspects of a re port that readers should evaluate to assess the comprehensiveness and appropriateness of the search strategy. Second, we describe the limita tions and decisions that most reviewers face when deciding how to asse ss trial quality and the aspects of a report that readers should evalu ate to determine how trial quality has been assessed and the appropria teness of the assessments.