Searches for systematic reviews aim to be as extensive as possible in order to ensure that as many as possible of the necessary and relevant studies are included in the review. It is, however, necessary to strike a balance between striving for comprehensiveness and maintaining relevance when developing a search strategy. Increasing the comprehensiveness (or sensitivity) of a search will reduce its precision and will retrieve more non-relevant articles
The goal is to maximize recall and precision while keeping the results manageable. Recall (sensitivity) is defined as the number of relevant reports identified divided by the total number of relevant reports in existence. Precision (specificity) is defined as the number of relevant reports identified divided by the total number of reports identified. Issues to consider:
TIP: Look for systematic reviews already published. This serves 2 purposes:
1. Makes sure that the work has not already been done
2. Provides examples of search strategies for your topic
AUTHORS AND LIBRARIANS:
IOM Standard 3.1; Conduct a comprehensive systematic search for evidence
3.1.1 Work with a librarian or other information specialist trained in performing systematic reviews to plan the search strategy
3.1.2 Design the search strategy to address each key research question
3.1.3 Use an independent librarian or other information specialist to peer review the search strategy
3.1.4 Search bibliographic databases
3.1.5 Search citation indexes
3.1.6 Search literature cited by eligible studies
3.1.7 Update the search at intervals appropriate to the pace of generation of new information for the research question being addressed
3.1.8 Search subject-specific databases if other databases are unlikely to provide all relevant evidence
3.1.9 Search regional bibliographic databases if other databases are unlikely to provide all relevant evidence
STANDARD 3.2 Take action to address potentially biased reporting of research results
3.2.1 Search grey literature databases, clinical trial registries, and other sources of unpublished information about studies
3.2.2 Invite researchers to clarify information about study eligibility, study characteristics, and risk of bias
3.2.3 Invite all study sponsors and researchers to submit unpublished data, including unreported outcomes, for possible inclusion in the systematic review
3.2.4 Handsearch selected journals and conference abstracts
3.2.5 Conduct a web search
3.2.6 Search for studies reported in languages other than English if appropriate
