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Systematic Reviews

Searching the literature

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Begin your search journey with a librarian!

Librarians can recommend databases and other sources to search for a systematic review. Check your home institution's database list for all of the available sources across all disciplines. To do this, go to "Find Articles" on the Priddy Library homepage. Choose your university in the drop-down menu and then click on "GO." 

Librarians can also help with designing complex searches using the specialized syntax of individual databases. Consult your subject librarian, if you have questions.

Search more databases to limit bias! Why?

“The conduct of the search for and selection of evidence may have serious implications for patients’ and clinicians’ decisions. A systematic review might lead to the wrong conclusions and, ultimately, the wrong clinical recommendations.” 


Finding Existing Systematic Reviews

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Searching for existing systematic reviews on a topic related to your own research question can be a good place to start. These systematic reviews may provide a model for approaching your own review of the literature, including recommended search strategies and resources. 

The following are links to online libraries of systematic reviews and evidence documents for health and other areas of policy-making.

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Appraising Systematic Reviews

Just because a review has been published as a "systematic review", it does not imply that the review was rigorous, reproducible or exhaustive. There are a number of criteria by which you can assess the quality of a systematic review.

The following article summarizes 44 critical appraisal tools.

Crowe, M., & Sheppard, L. (2011). A review of critical appraisal tools show they lack rigor: Alternative tool structure is proposed. Journal of Clinical Epidemiology, 64(1), 79–89.

Below are some common tools used for this purpose.

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Database Syntax

Every database works differently. Consult with a librarian to 'translate' searches between databases. The link below provides some guidance for how to search using different platforms.

  • Database syntax guide - A guide to database syntax provided by the Effective Practice and Organization of Care Cochrane Review group (EPOC).

Accessing Databases

You can access library databases from your home institution to find articles both on campus and off campus. 

Students from any university can access databases subscribed to by the University of Maryland, College Park (UMCP) Libraries while on campus at USG.

To access databases, go the Priddy Library homepage and go to the section that says, "Find Articles."  Select "USG" when on campus to access UMCP databases. To access databases from your home institution, select it in the drop-down menu and click GO.


How many and which databases to choose from?

There are systematic reviews in many subject areas such as education, social work, and even engineering where different databases are appropriate and very different conclusions would be reached. Some research is suggested below:

  • Agriculture: Ritchie, S.M., Young, L.M., & Sigman, J. (2018). A comparison of selected bibliographic database subject overlap for agricultural information. Issues in Science and Technology Librarianship, 89.
  • Education:
    • Borrego, M., Foster, M. J., & Froyd, J. E. (2014). Systematic literature reviews in engineering education and other developing interdisciplinary fields. Journal of Engineering Education, 103(1), 45–76.
    • Borrego, M., Foster, M. J., & Froyd, J. E. (2015). What is the state of the art of systematic review in engineering education? Journal of Engineering Education, 104(2), 212–242.
  • Engineering: Kitchenham, B. (2007). Guidelines for performing systematic literature reviews in software engineering. [Technical Report]. Keele, UK, Keele University, 33(2004), 1-26. - List of databases can be found on p. 17.
  • Health: Bramer, W. M., Rethlefsen, M. L., Kleijnen, J., & Franco, O. H. (2017). Optimal database combinations for literature searches in systematic reviews: A prospective exploratory study. Systematic Reviews, 6, 245.
  • Veterinary: Grindlay, D. J. C., Brennan, M. L., & Dean, R. S. (2012). Searching the veterinary literature: A comparison of the coverage of veterinary journals by nine bibliographic databases. Journal of Veterinary Medical Education, 39(4), 404–412.

Suggested databases for different subject areas

Check the institution names and icons next to the database names to determine, which ones you can access both on campus and off campus. For those with a UMCP icon, they can be accessed by faculty, students and staff from any institution while on campus. 

Agriculture, food and nutrition



Human health and medicine


Organizational development, economics and policy

Psychology, human development and other social sciences

Social Work

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This tab provides databases around the globe to find systematic reviews and other scholarly literature from national and international sources.

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What is grey literature?

Gray literature is defined by the Cochrane Handbook for Systematic Reviews of Interventions as "...literature that is not formally published in sources such as books or journal articles." This can include information such as government reports, conference proceedings, graduate dissertations, unpublished clinical trials, and much more.  

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Document your searches using the CADTH Grey Matters checklist, p. 3. It is a MS Word document where you fill in the blanks to say which website you searched, when you searched it, etc. 

How to find grey literature?

Tips and tricks
Comprehensive guide with resources
Free databases of grey literature
Theses and dissertations

UMD restricted access

International databases

Conference Proceedings

Off-campus access restricted to UMCP faculty, staff and students for most of these, unless otherwise noted. Available to all others on campus at USG.