Identifying systematic reviews in MEDLINE: developing an objective approach to search strategy design

Abstract

Background: systematic reviews are of increasing importance to health care professionals seeking to provide evidence-based health care, because they provide systematically prepared summaries of the current state of research knowledge on the effectiveness of health care interventions. To be able to make use of them, both researchers preparing systematic reviews and health care professionals need to be able to identify systematic reviews easily. In the past, systematic reviews have been difficult to identify easily among the mass of literature labelled ‘reviews’. Search strategies have been published which were intended to provide easier access to systematic reviews and meta-analyses. These strategies, mostly devised for the MEDLINE database, have been constructed using the authors’ knowledge of the subject area, the databases and past experience.

Objective: the objective of this study was to design search strategies based on a more objective approach to strategy construction.

Methods: word frequencies from the titles, abstracts and subject keywords of a collection of systematic reviews of the effective health care interventions were analysed to derive a highly sensitive search strategy.

Results: the proposed strategy offers 98% sensitivity in retrieving systematic reviews, while retaining a low but acceptable level of precision (20%). Other strategies with other levels of sensitivity and precision are also presented.

Discussion: this study shows that a frequency analysis approach can be used to generate highly sensitive strategies which retain adequate levels of precision when retrieving systematic reviews.

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References

[1] The Cochrane Library [database on disk and CD-ROM]. The Cochrane Collaboration ( Update Software, Oxford , 1996-). [Updated quarterly.]

[2] NHS Centre for Reviews and Dissemination , Undertaking Systematic Reviews of Research on Effectiveness: CRD Guidelines for Those Carrying Out or Commissioning Reviews ( NHS CRD, York , 1996).

[3] A.D. Oxman , Systematic reviews: checklists for review articles , British Medical Journal 309 (1994) 648-651 .

[4] NHS Centre for Reviews and Dissemination , Writing Abstracts for the Database of Abstracts of Reviews of Effectiveness (DARE): Summary of the Abstractors Manual ( NHS CRD, York , 1997). Available at: http://nhscrd.york.ac.uk/manual.htm

[5] G.V. Glass , Primary, secondary, and meta-analysis of research , Education Research 5 (1976) 3-8 .

[6] I. Chalmers and D.G. Altman , Foreword. In: I. Chalmers and D.G. Altman (eds), Systematic Reviews ( BMJ Publishing, London , 1995).

[7] The Knight Ridder Dialog bluesheet for MEDLINE is available at: http://www.krinfo.com/dialog/databases/netscape1.1/bl0154.html%23PU Knight Ridder has been taken over by MAID and the name of the service and the uniform resource locator (URL) may change.

[8] R.B. Haynes , C.D. Mulrow , E.J. Huth , D.G. Altman and M.J. Gardner , More informative abstracts revisited , Annals of Internal Medicine 113 (1990) 69-76 .

[9] National Library of Medicine , Medical Subject Headings. Annotated Alphabetic List 1997 ( NLM, Bethesda, MD , 1996).

10.

[10] K. Dickersin , K. Higgins and C.L. Meinert , Identification of meta-analyses: the need for standard terminology , Controlled Clinical Trials 11 (1990) 52-66 .

11.

[11] F.M. Wolf , C. Lefebvre and W.C. McGaghie , A trend analysis and search strategies for the identification of meta-analyses in MEDLINE (abstract) . In: Fourth International Cochrane Colloquium, Adelaide, 1996. Available at: http://som.flinders.edu.au/FUSA/COCHRANE/cochrane/abpos22.htm

12.

[12] D.L. Hunt and K.A. McKibbon , Locating and appraising systematic reviews , Annals of Internal Medicine 126 (1997) 532-538 .

13.

[13] Institute for Scientific Information , SCI Journal Citation Reports: A Bibliometric Analysis of Science Journals in the ISI Database, ( ISI, Philadelphia, PA , 1996).

14.

[14] C. Goodman , Literature Searching and Evidence Interpretation for Assessing Health Care Practices ( Swedish Council on Technology Assessment in Health Care, Stockholm , 1993), p. 27.

15.

[15] Blackwell Idealist. [computer program] July 1994. Multiple user variant ( Blackwell Software Publications, Oxford , 1994).

16.

[16] E. Egger , T. Zellweger Zahner , M. Schneider , C. Junker , C. Lengeler and G. Antes , Language bias in randomised controlled trials published in English and German , Lancet 350 (1997) 326-329 .

17.

[17] D. Moher, personal communication (1997). Dr Moher is based at the Clinical Epidemiology Unit of the Loeb Medical Research Institute, Ottawa, Canada, and is working on QUORUM (quality of reporting of meta-analysis).