title: Case-control confusion.
abstract: OBJECTIVE
  Critical analysis of journal articles by using principles of evidence-based medicine is important for clinicians applying research results in their practice and is a valuable component of pediatric residency training. Appraisal of an article's methodological rigor is often tailored to a particular type of study design, so that misclassification of study design can confuse the appraisal. The goal of this study was to determine how often pediatric research articles that are self-declared as case-control studies conform to a standard definition for this study design.
  
  
  METHODS
  A Medline search identified articles published in two pediatric journals from January 1996 through August 2004 with the phrase "case-control study" in the title or abstract. Articles that were self-declared as case-control studies were analyzed to determine whether they satisfied a standard definition of a case-control study.
  
  
  RESULTS
  Of the 91 purported case-control studies, only 68 (75%) met the standard definition for at least the most important analysis. The remaining 23 articles could be classified as cross-sectional studies (N = 16) or prospective cohort studies (N = 7).
  
  
  CONCLUSIONS
  Ambiguity in the definition of a case-control study can cause confusion in the critical appraisal of published clinical research.
authors.affiliation: Department of Pediatrics, University of Virginia Children's Hospital, Charlottesville, 22908, USA. mab4c@virginia.edu
authors.forename: Martha A
authors.initials: MA
authors.lastname: Hellems
authors.forename: Michael S
authors.initials: MS
authors.lastname: Kramer
authors.forename: Gregory F
authors.initials: GF
authors.lastname: Hayden
mesh_terms: D000293:Adolescent; D000295:Adolescent Medicine / Q000592:standards / Q000639:trends; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D010372:Pediatrics / Q000592:standards / Q000639:trends; D012107:Research Design; D012680:Sensitivity and Specificity