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Open Access Highly Accessed Research article

Optimal search strategies for detecting cost and economic studies in EMBASE

R James McKinlay1*, Nancy L Wilczynski1, R Brian Haynes12 and the Hedges Team

Author Affiliations

1 Health Information Research Unit, Department of Clinical Epidemiology and Biostatistics, McMaster University Medical Centre, 1200 Main Street West, Room 3H7, Hamilton, Ontario, Canada

2 Department of Medicine, Faculty of Health Sciences, McMaster University, 1200 Main Street West, HSC-2C10B, Hamilton, Ontario, Canada

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BMC Health Services Research 2006, 6:67  doi:10.1186/1472-6963-6-67

Published: 6 June 2006



Economic evaluations in the medical literature compare competing diagnosis or treatment methods for their use of resources and their expected outcomes. The best evidence currently available from research regarding both cost and economic comparisons will continue to expand as this type of information becomes more important in today's clinical practice. Researchers and clinicians need quick, reliable ways to access this information. A key source of this type of information is large bibliographic databases such as EMBASE. The objective of this study was to develop search strategies that optimize the retrieval of health costs and economics studies from EMBASE.


We conducted an analytic survey, comparing hand searches of journals with retrievals from EMBASE for candidate search terms and combinations. 6 research assistants read all issues of 55 journals indexed by EMBASE for the publishing year 2000. We rated all articles using purpose and quality indicators and categorized them into clinically relevant original studies, review articles, general papers, or case reports. The original and review articles were then categorized for purpose (i.e., cost and economics and other clinical topics) and depending on the purpose as 'pass' or 'fail' for methodologic rigor. Candidate search strategies were developed for economic and cost studies, then run in the 55 EMBASE journals, the retrievals being compared with the hand search data. The sensitivity, specificity, precision, and accuracy of the search strategies were calculated.


Combinations of search terms for detecting both cost and economic studies attained levels of 100% sensitivity with specificity levels of 92.9% and 92.3% respectively. When maximizing for both sensitivity and specificity, the combination of terms for detecting cost studies (sensitivity) increased 2.2% over the single term but at a slight decrease in specificity of 0.9%. The maximized combination of terms for economic studies saw no change in sensitivity from the single term and only a 0.1% increase in specificity.


Selected terms have excellent performance in the retrieval of studies of health costs and economics from EMBASE.