Key PointsQuestionCan deliberate practice (goal-oriented training with a coach who provides immediate, personalized performance feedback) improve diagnostic reasoning in trauma triage?FindingsIn this pilot randomized clinical trial of a novel deliberate practice intervention, 93% of participants received 3 planned coaching sessions, and most participants (93%) described the sessions as entertaining and valuable. During a simulation, the triage decisions of physicians in the intervention group were more likely to adhere to clinical practice guidelines than the triage decisions of physicians in the control group.MeaningThe deliberate practice intervention was feasible, acceptable, and effective in the laboratory, setting the stage for a future phase 3 clinical trial.