 The purpose of this paper was to summarize the current state of evidence synthesis and provide recommendations for improving its quality. The authors identified several common problems with evidence synthesis, such as lack of transparency, poor reporting, and biases in study selection and analysis. They also discussed the importance of using appropriate tools to evaluate the quality of evidence synthesis, including tools for assessing risk of bias, reporting, and methodological quality. Finally, they provided a concise guide to best practices for conducting evidence synthesis, which included preferred terminology and a classification scheme for different types of research evidence. This article was authored by Kat Kalasky, Lynn Romiza Logan, and John P. A. Ioannidis.