Overconfidence Leads to Less Medical Diagnostic Accuracy

A new study reveals that while female medical students answer medical questions correctly more often than their male counterparts, they express less confidence in their answers.

To examine the association between confidence and accuracy among medical students at Johns Hopkins School of Medicine (Baltimore, MD, USA), three students gathered data from a mobile web platform they developed called Osmosis, which consists of user-generated question banks from 14,000 participants. After answering a question, a user selects one of three confidence ratings: “I'm sure,” “Feeling lucky,” or “No clue.” The researchers analyzed the responses of 1,021 users (617 men and 404 women) who answered at least 50 questions. Gender was determined based on name, and ambiguous names were omitted.

The results showed that women's answers were accurate 61.4% of the time, compared with 60.3% of the men's answers. On the other hand, women selected “I'm sure” significantly less often than men did (39.5% versus 44.4% of responses, respectively). The women also averaged a higher accuracy in responses rated both “I'm sure” and “Feeling lucky” (80.5% versus 78.3%, and 53.5% versus 49.8%, respectively). The study was published as a letter on March 3, 2105, in Annals of Internal Medicine.

“The findings are a reminder that less confidence might not indicate a lack of knowledge, and that confidence should not be mistaken for correctness,” concluded lead author Jason Theobald, BA, an MD/MBA student at New York University School of Medicine (New York, USA), and colleagues. “The decision to split groups by gender ... followed after reading several papers that found similar gender differences with respect to confidence in different settings such as mock clinical scenarios.”

“There will always be a balance in medicine between running additional diagnostic tests and being reasonably confident about the diagnosis and plan given the (possibly limited) data at hand in a clinical setting,” said study coauthor MD candidate Ryan Haynes, PhD. “As a physician, if you lean too far in either direction you're either incurring additional costs and additional stress for the patient, or you're missing potentially important diagnostic criteria.”

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Johns Hopkins School of Medicine
New York University School of Medicine