Cochrane review: Search strategies to identify observational studies in MEDLINE and EMBASE

Observational studies provide important evidence for clinicians and policy makers to support their decision making.Systematic reviews of observational studies help answer research questions focusing on prognosis, cause, risk factors, and complications.However, when undertaking searches finding observational studies remains challenging because of the poor and inconsistent indexing in literature databases.Two main literature databases in healthcare are MEDLINE and Embase.To enable more effective and efficient retrieval of a particular type of study, literature search strategies can be complemented with methodological filters, that is, a collection of terms relating to a particular study design.The performance of a search strategy is normally evaluated by sensitivity (i.e., an ability to retrieve all relevant studies) and precision (i.e., an ability to retrieve relevant studies).In this Cochrane review, we aimed to collate evidence on performance of methodological filters as part of search strategies for identifying observational studies in MEDLINE and Embase.