Intended for healthcare professionals


Optimal search strategies for retrieving systematic reviews from Medline: analytical survey

BMJ 2005; 330 doi: (Published 06 January 2005) Cite this as: BMJ 2005;330:68
  1. Victor M Montori, assistant professor (bhaynes{at},
  2. Nancy L Wilczynski, doctoral student2,
  3. Douglas Morgan, data analyst2,
  4. R Brian Haynes, professor2
  5. for the Hedges Team
  1. 1Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
  2. 2Health Information Research Unit, Department of Clinical Epidemiology and Biostatistics, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada L8N 3J5
  1. Correspondence to: R B Haynes, Department of Clinical Epidemiology and Biostatistics, Room 2C10B Health Sciences Center, McMaster University Faculty of Health Sciences, 1200 Main Street West, Hamilton, ON, Canada L8N 3J5
  • Accepted 4 October 2004


Objective: To develop optimal search strategies in Medline for retrieving systematic reviews.

Design: Analytical survey.

Data sources: 161 journals published in 2000 indexed in Medline.

Main outcome measures: The sensitivity, specificity, and precision of retrieval of systematic reviews of 4862 unique terms in 782 485 combinations of one to five terms were determined by comparison with a hand search of all articles (the criterion standard) in 161 journals published during 2000 (49 028 articles).

Results: Only 753 (1.5%) of the 49 028 articles were systematic reviews. The most sensitive strategy included five terms and had a sensitivity of 99.9% (95% confidence interval 99.6% to 100%) and a specificity of 52% (51.6% to 52.5%). The strategy that best minimised the difference between sensitivity and specificity had a sensitivity of 98% (97% to 99%) and specificity of 90.8% (90.5% to 91.1%). Highest precision for multiterm strategies, 57% (54% to 60%), was achieved at a sensitivity of 71% (68% to 74%). The term “cochrane database of systematic reviews.jn.” was the most precise single term search strategy (sensitivity of 56% (52% to 60%) and precision of 96% (94% to 98%)). These strategies are available through the “limit” screen of Ovid's search interface for Medline.

Conclusions: Systematic reviews can be retrieved from Medline with close to perfect sensitivity or specificity, or with high precision, by using empirical search strategies.


  • Contributors VMM designed the protocol, analysed and interpreted the data, and drafted this report. NLW supervised the research staff and data collection. DM programmed the dataset and analysed the data. RBH planned the study, designed the protocol, and interpreted the data; he will act as guarantor. Members of the Hedges Team collected the data.

  • Funding This research was funded by the National Library of Medicine, USA (grant No 1 RO1 LM06866). VMM is a Mayo Foundation Scholar. These funding sources had no additional role.

  • Competing interests None declared.

  • Embedded Image A table showing PubMed translations of the Ovid search strategies is on

View Full Text