These encounters may be seen as representative of core distinguishing features relying on memory for these prior cases may be both an accurate and efficient way to sort between the features of one potential diagnosis relative to another. In the course of becoming an expert, a clinician will encounter hundreds of clinical cases. This early hypothesis generation process is presumed to be based on prior examples. Subsequent review of the patient history contributed a smaller amount to diagnostic performance (16%), while the physical exam and diagnostic tests did not influence clinicians’ diagnostic accuracy. In another study in a primary care setting, the accuracy of clinicians’ “diagnostic hypotheses” was 78% when based only on a review of the chief complaint alone. These early diagnostic hypotheses have been shown to determine final diagnostic accuracy if the correct diagnostic hypothesis was advanced in the first few minutes of a clinical encounter, clinicians were likely to be correct (95%), whereas if the hypothesis was not advanced in the first few minutes, the likelihood of an eventual accurate diagnosis was much lower (20%). The accuracy of medical residents and staff was not influenced by prior exposure.Ĭlassic work on diagnostic reasoning has established that clinicians propose an initial diagnostic hypothesis quite rapidly and very early in a patient encounter,. The differential diagnosis of pre-clerkship medical students improved with prior exposure, but this was unrelated to specific case or patient features. Accuracy for medical students was 84, 87, 94, and 73% for conditions a–d, respectively, interaction F(2,712)=3.55, p<0.002. When re-scored based on matching both equiprobable diagnoses, accuracy was high, but favored faculty (n=40) 98%, and residents (n=39) 98% over medical students (n=32) 85%, F(2,712)=35.6, p<0.0001. Resultsĭiagnosis A represented 47% of responses in condition d, but there was no influence of specific similarity of patient characteristics for Diagnosis A, F(3,712)=7.28, p=0.28 or Diagnosis B, F(3,712)=4.87, p=0.19. Cases with no prior exposure had no matched cases, hence validated the equiprobable design. A diagnosis consistent with a matched exposure case was scored correct. Participants diagnosed equiprobable cases that were: 1) matched to exposure cases (in one of three conditions: a) similar patient features, similar clinical features b) dissimilar patient features, similar clinical features c) similar patient features, dissimilar clinical features), or 2) not matched to any prior case (d) no exposure). The influence of prior exposures was measured using equiprobable clinical vignettes indicating two diagnoses. To create the experience of prior exposure, participants (pre-clerkship medical students, emergency medicine residents, and faculty) first verified diagnoses of clinical vignettes. The present study measured the influence of specific prior exposure and experience level on diagnostic accuracy. However, it is unclear whether this process influences diagnostic error rates or whether clinicians at all experience levels are equally susceptible. Diagnostic reasoning has been shown to be influenced by a prior similar patient case.