title: Quantitative comparison of pre-explosions and subheadings with methodologic search terms in MEDLINE.
abstract: OBJECTIVE
  To compare the retrieval characteristics of subheadings with methodologic textwords and MeSH terms in MEDLINE for identifying sound clinical studies on the etiology, prognosis, diagnosis, prevention and treatment of disorders in general adult medicine.
  
  
  METHODS
  Analytic survey of the information retrieval properties of methodologic textwords, single methodologic MeSH terms, pre-explosions and subheadings selected to detect studies meeting basic methodologic criteria for direct clinical use in general adult medicine.
  
  
  METHODS
  The sensitivity, specificity, and precision of search terms were determined by comparing the citations retrieved by the search strategies in MEDLINE with that of a manual review (the gold standard) of all articles in 10 internal and general medicine journals for 1986 and 1991.
  
  
  RESULTS
  For treatment and diagnosis in 1991, and treatment, diagnosis, and etiology in 1986, pre-explosions yielded the highest sensitivity, with typical absolute increases exceeding 15%. For etiology and prognosis in 1991, and prognosis in 1986, textwords or MeSH terms yielded the highest sensitivity. In all cases the increase in sensitivity was coupled with a loss in specificity and precision.
  
  
  CONCLUSIONS
  Compared with searching with single methodologic textwords and subject headings, the detection of sound clinical studies on the diagnosis and treatment of disorders in general adult medicine was consistently enhanced by searching with pre-explosions, but at a price of decreased specificity and precision.
authors.affiliation: Dept. of Clinical Epidemiology & Biostatistics, McMaster University, Hamilton, Ont., Canada.
authors.forename: N L
authors.initials: NL
authors.lastname: Wilczynski
authors.forename: C J
authors.initials: CJ
authors.lastname: Walker
authors.forename: K A
authors.initials: KA
authors.lastname: McKibbon
authors.forename: R B
authors.initials: RB
authors.lastname: Haynes
mesh_terms: D000043:Abstracting and Indexing; D016247:Information Storage and Retrieval / Q000706:statistics & numerical data; D016239:MEDLINE / Q000706:statistics & numerical data; D012680:Sensitivity and Specificity; D013358:Subject Headings