Validated geographic search filters for bibliographic databases: a scoping review

Objective: The purpose of this scoping review was to identify validated geographic search filters and report on their development and performance measures.
Introduction: The number of scientific publications has considerably increased. Measures to limit search and screening efforts can help to increase the efficiency of preparing systematic reviews. Search filters are useful tools for reviewers to identify reports with common characteristics in bibliographic databases. Geographic search filters limit literature search results to a specific geographic characteristic (eg, a country or region). Searching the literature using geographic filters can be useful in finding evidence about health care practices in distinct geographic regions; providing an overview of cultural, epidemiological, or health economics aspects; or indicating inequalities in health care in a certain region. Our aim was to identify validated geographic search filters and report on their development and performance measures.
Eligibility criteria: We included reports on validated geographic search filters aiming to identify research from or about defined geographic features (eg, countries/regions or groups of them).
Methods: This review was conducted in accordance with the JBI methodology for scoping reviews, as specified in an a priori protocol. We searched PubMed, Embase, the InterTASC Information Specialists' Sub-Group (ISSG) Search Filter resource, and Google Scholar. There were no date or language limitations on the searches. The study selection process was independently conducted by 2 reviewers, encompassing both abstract and full-text screening. The data extraction included basic characteristics of the geographic search filter (eg, country/region, database), methods used to develop and validate the search filters, and their performance measures. The extracted data were tabulated and summarized narratively.
Results: Our literature search yielded 907 hits. We included 9 reports that addressed 6 search filters for a broad range of geographic regions, including Spain, Africa, the United Kingdom, the United States, OECD countries as a group, as well as publications in high-ranking nursing journals from countries where German is spoken. The methods used for developing geographic search filters were heterogeneous. Gold standard sets were created by database searching (n = 3; 50%) and relative recall (n = 3; 50%). Only 3 filters were created using objective methods and 2 underwent internal validation. The sensitivity of the search filters ranged from 73% to nearly 100%.
Conclusion: The findings show that validated geographic search filters are not widely available. The identified search filters may serve as methodological outlines for the development of search filters for other countries or geographic regions. The calculation methods for specificity were different, which made comparison difficult. Further efforts to standardize the methods for developing and validating these filters, as well as reporting, are important to increase their reliability and comparability.