The efficiency of database searches for creating systematic reviews was improved by search filters

To compare Clinical Queries (CQs) for randomized trials of therapy 'methods' and 'NOT' limits search filters with Cochrane methods filters.

Analytic survey of Cochrane reviews as the reference standard for retrieving studies included in the reviews ("included studies [ISs]"). The sensitivity and precision of Cochrane content terms + Cochrane methods terms were compared in MEDLINE and Embase with Cochrane content terms + CQs maximally sensitive filter for therapy studies, without and with additional 'NOT' limits (CQ-S [CQ sensitive]; CQ-S + limits) and a balanced filter without and with additional NOT limits (CQ-B [CQ balanced]; CQ-B + limits).

Cochrane or CQ methods terms reduced, by 64-96%, the overall retrieval of articles with minimal loss of ISs. Sensitivity was high and similar for the 4 filters. However, CQ-B + limits had the highest precision (2.64%, number needed to be read to find one eligible study [NNR] 38) followed by the CQ-B (1.05%, NNR 95), Cochrane search (0.51%, NNR 198), CQ-S + limits (0.34%, NNR 296), and CQ-S filters (0.31%, NNR 325).

For systematic reviews of therapeutic interventions, the efficiency of searches in MEDLINE and Embase was better served by the CQs for therapy studies with balanced methods filter and NOT limits.