by MarksMan Healthcare | 0 Comments Information Retrieval , Search Strategy , Systematic Literature Reviews
Systematic literature reviews (SLR) are a crucial tool to identify high-quality evidence for research, policy, and practice. The success of SLRs heavily relies on the performance of the literature search strategy, which involves utilizing appropriate information retrieval (IR) techniques to locate relevant studies. (1,2) Appropriate IR techniques are essential to capture all relevant studies, and to avoid retrieving irrelevant studies as far as possible. (3) In this direction, systematic reviewers often use combination of specific search strings, Boolean operators, limits and search filters to optimize the search strategy, and also to ensure that the search is comprehensive, systematic, and reproducible. (4,5)
Search filters are tools that help to retrieve certain types of records based on their characteristics, such as methodology, study design, or publication type. Filters can be applied to various aspects of the search, such as the population, intervention, study design, and so on, and are usually guided by the PICOS of the SLR. For example, while conducting an SLR on the clinical efficacy and safety of a specific intervention, a filter may be applied to only include randomized controlled trials (RCTs) involving the specific intervention and a predefined set of comparators. (5) On the other hand, ‘limits’ in a search strategy restricts the number of search results by setting a predefined maximum number of results, and can be based on aspects such as publication type, language, or publication year. For example, for updating a previously published SLR, a limit may be used to restrict the search results for the past 5 years. Other examples for limits include country restrictions and language restrictions. (6)
Having a comprehensive search strategy without any restrictions or limits is highly desirable for pooling together all relevant research to help unbiassed evidence synthesis. However, at times, researchers will need to use limits in search strategy to optimize the literature search process and make the SLR more time-efficient:
That said, using limits are associated with certain disadvantages:
At times it becomes essential to use limits in search strategy for various reasons. In such cases, the following guidelines may be helpful to utilise the advantages of the limits while reducing their disadvantages:
The use of limits in literature searching requires a balanced approach. If used with proper justification, they can help refine search results and improve the review’s precision, and also ensure timely completion of SLR. (10) Systematic reviewers must weigh the benefits and potential drawbacks of limiting their search, make informed decisions based on the research question and the scope of the review. By using limits appropriately and judiciously, it is possible to improve the accuracy and efficiency of literature searches and thus produce a high-quality SLR.
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