Literature reviews aim to retrieve all results that are relevant to your topic through systematic searching. Review searches can be quite extensive and retrieve a large numbers of results, and an important aspect of systematic searching is how to limit the number of irrelevant results that will need to be screened. Librarians are experts trained in literature searching and systematic review methodology, and partnering with a librarian can save you time and improve the quality of your review.

There is almost always a trade-off between comprehensiveness and relevance when searching.  For example, many systematic reviews are very extensive because the goal is to find all relevant studies on a topic. In order to find all these studies, the range of the search is increased but this also means that more non-relevant articles will be retrieved.

When conducting a search according to literature review methods, keep the following in mind:

• Included all relevant concepts of the research question in the strategy
• Use appropriate subject headings
• Use appropriate subject heading features, such as subheadings or the explosion or main topic options
• Use natural language (free text words) in addition to controlled vocabulary terms
• Use appropriate synonyms, acronyms, etc.
• Apply truncation and spelling variation as appropriate
• Apply appropriate limits, such as language, years of publication, etc.
• Apply field searching or filters appropriate, such as publication type, etc.
• Insure that Boolean operators are used correctly
• Check for line errors when searches are combined using line numbers
• Check indexing of relevant articles
• Adapt the search strategy for multiple databases

• Chapter 4: Searching for and selecting studies from the Cochrane Handbook for Systematic Reviews of Intervention
• Systematic Review Information Retrieval Checklist from Campbell Collaboration
• De Brún, C., & Pearce-Smith, N. (2014). Searching skills toolkit: finding the evidence  (Second edition.). Wiley.