title: The influence of types of decision support on physicians' decision making.
abstract: OBJECTIVE
  To determine whether physicians' post-test probability estimates are influenced by receiving test characteristics and impact their subsequent clinical decisions.
  
  
  METHODS
  Questionnaire based randomised controlled trial.
  
  
  METHODS
  Mailed survey with a vignette describing an infant whose pretest likelihood of pertussis was 30% and direct fluorescent-antibody (DFA) test was negative for pertussis.
  
  
  METHODS
  Nationally representative sample of US paediatricians (n = 1502).
  
  
  METHODS
  Random receipt of no additional information (controls), the DFA's sensitivity and specificity (TC group) or the test's sensitivity and specificity with their definitions (TCD group).
  
  
  METHODS
  Estimated post-test probability (PTP) of pertussis, PTP of 0.50, "nearly correct" PTP (+/-5%), intended erythromycin management and intended hospital disposition.
  
  
  METHODS
  Chi2 and t tests.
  
  
  RESULTS
  Despite the negative DFA result, 67% of the 635 (49.7%) participants who responded estimated a PTP higher than the pretest probability of 30%; the overall mean estimated PTP was 0.41 (SD 0.26) (correct answer: 0.18). The TCD group's mean PTP was significantly higher than controls' mean PTP (0.45 vs 0.38, p<0.001), while the TC and control groups' mean PTP did not differ significantly (0.41 vs 0.38, p = 0.16). With decision support significantly more TC and TCD participants compared to controls estimated the PTP as 0.50 (38% vs 17%, p<0.001; 41% vs 17%, p<0.001, respectively) and also estimated a nearly correct PTP more often (20% vs 13%, p = 0.06; 19% vs 13%, p = 0.08, respectively). The mean PTP of participants intending to discontinue erythromycin therapy or discharge the patient home was significantly lower than that of participants who intended continuing erythromycin or hospitalisation (0.20 vs 0.43, p<0.001; 0.40 vs 0.49, p = 0.005, respectively).
  
  
  CONCLUSIONS
  Paediatricians differed in their response to information about test characteristics. For many, it increased errors in estimating post-test probability; for others, it reduced errors. Estimated post-test probability was logically associated with intended clinical management.
authors.affiliation: Department of Pediatrics, Boston Medical Center and Boston University School of Medicine, Boston, MA 02118, USA. colin.sox@bmc.org
authors.forename: C M
authors.initials: CM
authors.lastname: Sox
authors.forename: J N
authors.initials: JN
authors.lastname: Doctor
authors.forename: T D
authors.initials: TD
authors.lastname: Koepsell
authors.forename: D A
authors.initials: DA
authors.lastname: Christakis
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D002648:Child; D002983:Clinical Competence; D003657:Decision Making; D003661:Decision Support Techniques; D004311:Double-Blind Method; D004917:Erythromycin / Q000627:therapeutic use; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D012680:Sensitivity and Specificity; D014917:Whooping Cough / Q000175:diagnosis* / Q000188:drug therapy
chemical_list: D000900:Anti-Bacterial Agents; D004917:Erythromycin