For a sample of 200 recently published systematic reviews, we calculated how many had used enough databases to ensure 95% recall. We assessed the frequency at which databases and combinations would achieve varying levels of recall (i.e., 95%). Using the prospectively recorded results and the studies included in the publications, we calculated recall, precision, and number needed to read for single databases and databases in combination. For each published systematic review, we extracted the references of the included studies. PubMed was used to identify systematic reviews published using our search strategy results. Since May 2013, the first author prospectively recorded results from systematic review searches that he performed at his institution. While previous studies determined the coverage of databases, we analyzed the actual retrieval from the original searches for systematic reviews. We aimed to determine the optimal combination of databases needed to conduct efficient searches in systematic reviews and whether the current practice in published reviews is appropriate.

However, searching databases is laborious and time-consuming, as syntax of search strategies are database specific. Within systematic reviews, when searching for relevant references, it is advisable to use multiple databases.

In search of the lost future download