Evaluation of the start of surgical closure as a milestone for forecasting the time remaining to exit the operating room: A retrospective, observational cohort study

•Once a case exceeds the average closing time, there is a near constant time to room exit.•At closing, a countdown timer, initiated with the mean interval to room exit, might be useful.•However, exit times’ proportional variability is too large for accurate forecasting.•Published methods to predict time remaining in cases can be adapted to predict exit times.•The data for such prediction of exit times are readily available in the electronic health record.