Objective: Accurate measurement of physicians' time spent during patient care stands to inform emergency department (ED) improvement efforts. Direct observation is time consuming and cost prohibitive, so we sought to determine if physician self-estimation of time spent during patient care was accurate.

Methods: We performed a prospective, convenience-sample study in which research assistants measured time spent by ED physicians in patient care. At the conclusion of each observed encounter, physicians estimated their time spent. Using Mann-Whitney U tests and Spearman's rho, we compared physician estimates to actual time spent and assessed for associations of encounter characteristics and physician estimation.

Results: Among 214 encounters across 10 physicians, we observed a medium-sized correlation between actual and estimated time (Spearman's rho = 0.63, p < 0.001), and in aggregate, physicians underestimated time spent by a median of 0.1 min. An equal number of encounters were overestimated and underestimated. Underestimated encounters were underestimated by a median of 5.1 min (interquartile range [IQR] 2.5-9.8) and overestimated encounters were overestimated by a median of 4.3 min (IQR 2.5-11.6)-26.3% and 27.9% discrepancy, respectively. In terms of actual time spent, underestimated encounters (median 19.3 min, IQR 13.5-28.3) were significantly longer than overestimated encounters (median 15.3 min, IQR 11.3-20.5) (p < 0.001).

Conclusions: Physician self-estimation of time spent was accurate in aggregate, providing evidence that it is a valid surrogate marker for larger-scale process improvement and research activities, but likely not at the encounter level. Investigations exploring mechanisms to augment physician self-estimation, including modeling and technological support, may yield pathways to make self-estimation valid also at the encounter level.