Daily output measures of Emergency Department in association with seasonality and day of the week: A retrospective cohort observational study.

To evaluate the daily output measures of the emergency department (ED) in association with seasonality and the day of the week. A retrospective cohort of ED visits to tertiary medical centers between 2016 and 2020. The research unit was each day during the study period. The independent variables were season and day of the week. The dependent variables were ED visits, admission and dropout rates, and duration of ED discharge. The comparison of means was evaluated using ANOVA. Statistical significance was set at P < .05. There were 1826 days, 792 thousand visits, 58% were female. Admission rate 28%, duration to discharge 3.8 h, dropout rate 2%. The average daily visits by season ranged from 101% of the overall average in autumn to 97% in spring. Average daily visits by day of the week were significantly different, with the highest on Sunday (Israel's first working day of the week), 124% of the overall daily average, and the lowest on Saturday (weekly day off) with 70%. Saturdays had the highest admission rate of 30% and 28% of the overall rate. There was a moderate dependency between the ED duration and discharge, with a dropout rate of r2 = 0.19. The average daily visits were not affected by season but differed considerably by day of the week. Admission rates varied slightly by season but were similar by day of the week apart from Saturdays. This may be attributable to the case mix on Saturdays or less restriction to admit when the number of visits is low. We recommended each Emergency Department to evaluate its daily output measures dependency with seasonality and day of the week for operational optimization.