Principles in the Evaluation of Systematic Reviews.

Literature reviews summarize information from individual studies and are an important tool in the practice of evidence-based medicine. Various types of reviews, including narrative and systematic reviews, may be found within the biomedical literature. Systematic reviews are the strongest type and are often rated as the highest level of evidence. Thus it is important that clinicians understand how to evaluate them critically. This article is intended to enhance clinicians' understanding of the unique methods commonly used in systematic reviews by using the reporting standards to formulate evaluation principles. Explanations of the statistical tests and types of biases that are frequently encountered in systematic reviews are discussed. Lastly, an evaluation of a meta-analysis using these principles is provided.