title: How do physicians decide to treat: an empirical evaluation of the threshold model.
abstract: BACKGROUND
  According to the threshold model, when faced with a decision under diagnostic uncertainty, physicians should administer treatment if the probability of disease is above a specified threshold and withhold treatment otherwise. The objectives of the present study are to a) evaluate if physicians act according to a threshold model, b) examine which of the existing threshold models [expected utility theory model (EUT), regret-based threshold model, or dual-processing theory] explains the physicians' decision-making best.
  
  
  METHODS
  A survey employing realistic clinical treatment vignettes for patients with pulmonary embolism and acute myeloid leukemia was administered to forty-one practicing physicians across different medical specialties. Participants were randomly assigned to the order of presentation of the case vignettes and re-randomized to the order of "high" versus "low" threshold case. The main outcome measure was the proportion of physicians who would or would not prescribe treatment in relation to perceived changes in threshold probability.
  
  
  RESULTS
  Fewer physicians choose to treat as the benefit/harms ratio decreased (i.e. the threshold increased) and more physicians administered treatment as the benefit/harms ratio increased (and the threshold decreased). When compared to the actual treatment recommendations, we found that the regret model was marginally superior to the EUT model [Odds ratio (OR) = 1.49; 95% confidence interval (CI) 1.00 to 2.23; p = 0.056]. The dual-processing model was statistically significantly superior to both EUT model [OR = 1.75, 95% CI 1.67 to 4.08; p < 0.001] and regret model [OR = 2.61, 95% CI 1.11 to 2.77; p = 0.018].
  
  
  CONCLUSIONS
  We provide the first empirical evidence that physicians' decision-making can be explained by the threshold model. Of the threshold models tested, the dual-processing theory of decision-making provides the best explanation for the observed empirical results.
authors.affiliation: Department of Internal Medicine, Division of Evidence-based Medicine and Health Outcomes Research, University of South Florida, Tampa, FL, USA. bdjulbeg@health.usf.edu.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Djulbegovic
authors.forename: Shira
authors.initials: S
authors.lastname: Elqayam
authors.forename: Tea
authors.initials: T
authors.lastname: Reljic
authors.forename: Iztok
authors.initials: I
authors.lastname: Hozo
authors.forename: Branko
authors.initials: B
authors.lastname: Miladinovic
authors.forename: Athanasios
authors.initials: A
authors.lastname: Tsalatsanis
authors.forename: Ambuj
authors.initials: A
authors.lastname: Kumar
authors.forename: Jason
authors.initials: J
authors.lastname: Beckstead
authors.forename: Stephanie
authors.initials: S
authors.lastname: Taylor
authors.forename: Janice
authors.initials: J
authors.lastname: Cannon-Bowers
mesh_terms: D000328:Adult; D000368:Aged; D003657:Decision Making; D019317:Evidence-Based Medicine; D005260:Female; D019538:Health Care Surveys / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D010820:Physicians / Q000592:standards*; D011582:Psychological Theory; D016032:Randomized Controlled Trials as Topic / Q000592:standards; D020711:Threshold Limit Values