title: Can female adolescents tell whether they will test positive for Chlamydia infection?
abstract: OBJECTIVE
  Having better predictors of chlamydia infection may improve health care providers' decisions about when to provide testing for Chlamydia trachomatis (Ct). Adolescents' probability judgments of significant life events in the next year and by age 20 y have shown promising validity, being significantly correlated with subsequent self-reports of having experienced these events. Here, the authors examine whether female adolescents' probability judgments of having chlamydia were correlated with the objective outcome of a Ct polymerase chain reaction assay.
  
  
  METHODS
  Three hundred sexually active female adolescents were recruited from urban health care clinics in Pittsburgh. They assessed ''the percent chance that you have chlamydia right now,'' then answered questions about their demographic background and sexual history. Subsequently, the authors tested for Ct infection using a self-administered introital swab.
  
  
  RESULTS
  Adolescents' probability judgments of having chlamydia ''right now'' were correlated with whether they tested positive for Ct infection, even after controlling for demographic variables and sexual history. This result held when probability judgments were dichotomized in terms of whether adolescents had assigned a zero or nonzero probability. Adolescents' mean probability judgment was less than their infection rate, indicating that, on average, they underestimated their actual risk.
  
  
  CONCLUSIONS
  Adolescents can tell whether they are at increased risk for chlamydia but may need better information about its absolute magnitude. Eliciting adolescents' probability judgments of having chlamydia can add value to clinical decision making.
authors.affiliation: Department of Social and Decision Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA. wandi@cmu.edu
authors.forename: Wändi
authors.initials: W
authors.lastname: Bruine de Bruin
authors.forename: Julie S
authors.initials: JS
authors.lastname: Downs
authors.forename: Pamela
authors.initials: P
authors.lastname: Murray
authors.forename: Baruch
authors.initials: B
authors.lastname: Fischhoff
mesh_terms: D000293:Adolescent; D000367:Age Factors; D015415:Biomarkers; D002690:Chlamydia Infections / Q000175:diagnosis*; D002692:Chlamydia trachomatis; D005260:Female; D007722:Health Knowledge, Attitudes, Practice; D006306:Health Surveys; D006801:Humans; D016133:Polymerase Chain Reaction; D015203:Reproducibility of Results; D018570:Risk Assessment; D012309:Risk-Taking; D012725:Sexual Behavior; D012959:Socioeconomic Factors; D016387:Women's Health
chemical_list: D015415:Biomarkers