A comparison of initial diagnostic hypotheses of medical students and internists.

Medical students and board-certified general internists were presented with two written clinical simulations and asked to list their initial diagnostic hypotheses. Bronchial asthma and respiratory infection were among the three most frequently listed causes of a sudden shortness of breath in a young male, while malignancy, depression, and thyrotoxicosis were among the six most frequently listed causes of fatigue and loss of weight in a young woman. Junior medical students in the preclinical phase of the curriculum responded with fewer and less specific initial diagnostic hypotheses than did the internists. The number and specificity of the hypotheses advanced by senior medical students, who had completed the medical clerkship, were similar to those of the internists. However, the senior students advanced a wider range of diagnostic possibilities, some of which are rare or virtually nonexistent in the age groups of the patients in the simulations. These findings identify two deficiencies in students' diagnostic problem-solving: (a) lack of familiarity with alternative diagnostic possibilities and (b) poor ability to consider diagnostic hypotheses in terms of probabilities.