The pages here will provide an introduction to constructing comprehensive searches in the health sciences resources. However, the best course of action is to consult with a librarian for individual guidance. Refer to the Hardin Services page for additional details or contact the librarian for your subject area directly.

Reviews that aim to minimize chance of bias may include additional sources after database searching is completed. Depending on the topic, one or all of the below methods may be appropriate. A librarian can help develop an appropriate plan.

• Grey Literature: Grey literature includes unpublished studies, reports, conference proceedings, and other materials from professional organizations or governmental agencies. Grey literature may be challenging to locate. Unpublished studies should be consulted to reduce the risk of publication bias in results.
• References: Reviewing reference lists from selected articles can turn up other studies that were missed during the searching phase.
• Hand Searching: This involves Identifying key journals for the topic and manually searching table of contents or using electronic journal search interface.
• Citing Papers: Reviewing citing papers from key relevant studies on the topic may yield additional results not captured. Citation resources include Google Scholar, Web of Science, and Scopus.

The National Academies of Sciences, Engineering, and Medicine recommends working with a librarian or other information specialist to design the search strategy for a systematic review. Typically at least three databases are used for a systematic review.

Projects completed with librarian support have been associated with higher quality reporting of methods.See references below:

Rethlefsen, M. L., Farrell, A. M., Osterhaus Trzasko, L. C., & Brigham, T. J. (2015). Librarian co-authors correlated with higher quality reported search strategies in general internal medicine systematic reviews. Journal of Clinical Epidemiology, 68(6), 617-626. https://doi.org/10.1016/j.jclinepi.2014.11.025 view full text

Koffel, J. B. (2015). Use of recommended search strategies in systematic reviews and the impact of librarian involvement: a cross-sectional survey of recent authors. PloS One, 10(5), e0125931. https://doi.org/10.1371/journal.pone.0125931 view full text

Schellinger, J., Sewell, K., Bloss, J. E., Ebron, T., & Forbes, C. (2021). The effect of librarian involvement on the quality of systematic reviews in dental medicine. PloS One, 16(9), e0256833. https://doi.org/10.1371/journal.pone.0256833 view full text