To compare the diagnostic processes of experienced emergency physicians w~th those of novices.
Design: Prospective, convenience sample of patients.
Setting: Emergency department of a county university medical center in a large southwestern urban community.
Participants: Experienced emergency physicians (attending and senior residents) and novice clinicians (junior residents and senior medical students).
Interventions: Participants developed initial diagnostic impressions after reviewing the chief complaint, nurse triage notes, and vital signs. Tests were then selected, and a final diagnostic impression was identified after results were known. Clinicians also marked a visual analog scale corresponding to their estimate that each diagnostic possibility was correct.
Results: Experienced physicians increased their certainty more than novices (P = .014). They deviated from a standard history-physical-laboratory sequence more often than novices (P = .008).
Conclusion: Expertise in medical decision making is characterized by a moderate initial level of certainty concerning a diagnosis that significantly increases as the experienced clinician follows a flexible Strategy of testing to arrive at a final diagnosis.