Developing your search strategy is the key to ensuring that you find the right kind of evidence for your systematic review. Your search strategy refers to the specific keywords and connectors you will use to find relevant literature. The search terms for each one of your concepts should consist of both subject headings where available, as well as keywords, in order to increase the sensitivity of the search.
Keywords are words or phrases that can be searched for in different database fields such as title, abstract, author keywords, journal etc. Revisiting your research question will help you determine the relevant terms.
Subject headings are assigned to bibliographic records in a database by indexers in order to identify the main concepts of an article. Different databases use their own subject heading classification systems.
Search strategies for systematic reviews can be incredibly complex, and require you to have knowledge of searching techniques such as Boolean logic (the use of AND, OR, NOT to connect terms together).
For example:
handwashing OR hand sanitizing OR hand hygiene
AND
emergency room
The same example using a Medical Subject Heading (MeSH term) from Ovid Medline(R) ALL:
handwashing OR hand sanitizing OR hand hygiene OR Hand Disinfection/
AND
emergency room
Language limits should not be applied to search strategies that are intended to be as comprehensive as possible. Reviewers should attempt to identify all relevant studies, regardless of language, to reduce the likelihood of publication bias. If it is not possible to have non-English-language studies translated, the review should report the number of non-English-language studies that were eligible but not included in the review. For more information, refer to the section on language bias in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins, 2019, Section 7.2.3).
Date restrictions may be appropriate for updating previously published systematic reviews.
Limiting to specific study types and to human subjects is usually done using a combination of keyword and subject headings (not by using database filters). Please contact a librarian for more information on how to use these limiters in your search.