title: Impact of PubMed search filters on the retrieval of evidence by physicians.
abstract: BACKGROUND
  Physicians face challenges when searching PubMed for research evidence, and they may miss relevant articles while retrieving too many nonrelevant articles. We investigated whether the use of search filters in PubMed improves searching by physicians.
  
  
  METHODS
  We asked a random sample of Canadian nephrologists to answer unique clinical questions derived from 100 systematic reviews of renal therapy. Physicians provided the search terms that they would type into PubMed to locate articles to answer these questions. We entered the physician-provided search terms into PubMed and applied two types of search filters alone or in combination: a methods-based filter designed to identify high-quality studies about treatment (clinical queries "therapy") and a topic-based filter designed to identify studies with renal content. We evaluated the comprehensiveness (proportion of relevant articles found) and efficiency (ratio of relevant to nonrelevant articles) of the filtered and nonfiltered searches. Primary studies included in the systematic reviews served as the reference standard for relevant articles.
  
  
  RESULTS
  The average physician-provided search terms retrieved 46% of the relevant articles, while 6% of the retrieved articles were relevant (corrected) (the ratio of relevant to nonrelevant articles was 1:16). The use of both filters together produced a marked improvement in efficiency, resulting in a ratio of relevant to nonrelevant articles of 1:5 (16 percentage point improvement; 99% confidence interval 9% to 22%; p < 0.003) with no substantive change in comprehensiveness (44% of relevant articles found; p = 0.55).
  
  
  CONCLUSIONS
  The use of PubMed search filters improves the efficiency of physician searches. Improved search performance may enhance the transfer of research into practice and improve patient care.
authors.affiliation: Division of Nephrology, University of Western Ontario, London, Ont. salimah.shariff@lhsc.on.ca
authors.forename: Salimah Z
authors.initials: SZ
authors.lastname: Shariff
authors.forename: Jessica M
authors.initials: JM
authors.lastname: Sontrop
authors.forename: R Brian
authors.initials: RB
authors.lastname: Haynes
authors.forename: Arthur V
authors.initials: AV
authors.lastname: Iansavichus
authors.forename: K Ann
authors.initials: KA
authors.lastname: McKibbon
authors.forename: Nancy L
authors.initials: NL
authors.lastname: Wilczynski
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Weir
authors.forename: Mark R
authors.initials: MR
authors.lastname: Speechley
authors.forename: Amardeep
authors.initials: A
authors.lastname: Thind
authors.forename: Amit X
authors.initials: AX
authors.lastname: Garg
mesh_terms: D003625:Data Collection; D019317:Evidence-Based Medicine; D006801:Humans; D057226:Information Seeking Behavior; D007674:Kidney Diseases / Q000628:therapy; D010820:Physicians; D039781:PubMed / Q000458:organization & administration / Q000592:standards