 In this study, the authors examined the effectiveness of different databases in systematic reviews. They found that combining in-base, Medline, Web of Science Core Collection, and Google Scholar provided the highest recall rate of 98.3%, with 100% recall in 72% of systematic reviews. This suggests that these four databases provide the best coverage for systematic reviews. Additionally, they estimated that 60% of published systematic reviews do not retrieve 95% of all available relevant references, indicating that more comprehensive search is unnecessary to ensure adequate and efficient coverage. This article was authored by Witcher Embraer, Melissa L. Wreth Lefson, Joe Skleinen, and others.