Swapping horses midstream: factors related to physicians' changing their minds about a diagnosis.

Purpose: Premature closure has been identified as the single most common cause of diagnostic error. This factorial experiment explored which variables exert an unconfounded influence on physicians' diagnostic flexibility (changing their minds about the most likely diagnosis during a clinical case presentation).

Method: In 2007-2008, 256 practicing physicians viewed a clinically authentic vignette simulating a patient presenting with possible coronary heart disease (CHD) and provided their initial impression midway through the case. At the end, they answered questions about the case, indicated how they would continue their clinical investigation, and made a final diagnosis. The authors used general linear models to determine which patient factors (age, gender, socioeconomic status, race), physician factors (gender, age/experience), and process variables were related to the likelihood of physicians' changing their minds about the most likely diagnosis.

Results: Physicians who had less experience, those who named a non-CHD diagnosis as their initial impression, and those who did not ask for information about the patient's prior cardiac disease history were the most likely to change their minds. Participants' certainty in their initial diagnosis, the additional information desired, the diagnostic hypotheses generated, and the follow-up intended were not related to the likelihood of change in diagnostic hypotheses.

Conclusions: Although efforts encouraging physicians to avoid cognitive biases and to reason in a more analytic manner may yield some benefit, this study suggests that experience is a more important determinant of diagnostic flexibility than is the consideration of additional diagnoses or the amount of additional information collected.