Systematic reviews and meta-analyses are important ways to summarize the scientific literature with a priori–specified criteria to answer a specific research question. When evidence accumulates with increasing numbers of trials and results sometimes seem contradictory or different in magnitude of effect, a state-of-the-art statistical summary is needed to reach an aggregated conclusion. They are increasingly important in developing clinical practice guidelines, collating empirical evidence from studies to investigate controversial research questions, informing policy makers, and justifying future research. Approximately 2500 new systematic reviews and meta-analyses are published and indexed annually.¹ However, systematic reviews and meta-analyses are only as good as the included literature and may be biased if an inadequate search strategy results in inclusion of poor-quality literature.