Background Framing bias occurs when people make a decision based on the way the information is presented, as opposed to just on the facts themselves. How the diagnostician sees a problem may be strongly influenced by the way it is framed. Does framing bias result in clinically meaningful diagnostic error?

Methods We created three hypothetical cases and asked consultants and registrars in Emergency Medicine and Internal Medicine to provide their differential diagnoses and investigations list. Two of the presentations were written two ways to frame the case towards or away from a particular diagnosis (Presentation 2 – pulmonary embolus (PE) and Presentation 3 – interstitial lung disease (ILD)) and these were randomly assigned to the participants. Both versions were however entirely identical in terms of the objective facts. Physician impressions and diagnostic plan were compared. A third presentation was identical for all and served as a control for clinician baseline ‘risk-averseness’.

Results There were significant differences in the differential diagnoses generated depending on the presentation’s framing. PE and ILD were considered and investigated for the majority of the time when the presentation was framed towards these diagnoses, and the minority of the time when it was not. This finding was most striking in Presentation 2, where 100%versus50% of clinicians considered PE in their diagnosis when the presentation was framed towards PE. This result remained robust when undertaking stratified analysis and logistic regression to account for differences in seniority and baseline risk-averseness— neither of the latter variables had any effect on the result.

Conclusion We demonstrate a clinically meaningful effect of framing bias on diagnostic error. The strength of our study is focus on clinically meaningful outcomes: investigations ordered. This finding has implications for the way we conduct handovers and teach juniors to communicate clinical information.