Appraisal of: "Li L, Smith HE, Atun R, Tudor Car L. Search strategies to identify observational studies in MEDLINE and Embase. Cochrane Database Systematic Reviews 2019, Issue 3. Art. No.: MR000041. DOI:10.1002/14651858.MR000041.pub2”

Reviewer(s): 
Short description: 

The objective of this review was to assess the sensitivity and precision of a search strategy with a methodological filter to identify observational studies in MEDLINE and Embase.

In April 2018 the Authors searched Medline, Embase, CINAHL, the Cochrane Library, Google Scholar, Open Grey and scanned reference list for articles.

The two studies included tested 18 filters in total which used different approaches.

Using search filters for identifying observational studies for systematic reviews  is not recommended and further research should be undertaken.

Limitations stated by the author(s): 
  • Focus of these search strategies was different: one study focused on retrieval of observational studies of surgical interventions and the other on non-randomised studies
  • Studies were published 10 years before the date of this systematic review and indexing of observational studies has changed in the meantime
  • Authors were unsure of the reliability of the reported performance data due to the lack of external validation for most search filters and methodological limitations
Limitations stated by the reviewer(s): 
• The review included only two studies • Heterogeneity between studies • Search was not updated before publication and therefore may have missed more recent publications
Study Type: 
Review