Background: Tardiness from scheduled start times in a surgical suite is a common source of frustration for both operating room personnel and patients.
Methods: Data from two surgical suites were used to investigate the relative importance of various factors that contribute to tardiness, including average case duration, time of day, prolonged turnovers, whether a surgeon follows himself or another surgeon, the potential for starting cases early, concurrency (e.g., number of residents supervised simultaneously), expected under-utilized or over-utilized time, and case duration bias.
Results: Average tardiness per case did not depend on the individual durations of preceding cases or on the relative numbers of long and short cases. In contrast, the total duration of preceding cases was important in determining tardiness. Tardiness per case grew larger as the day progressed because the total duration of preceding cases increased, but began to decline for cases scheduled to commence 6 h after the start of the workday. Tardiness was not affected by prolonged turnovers, differences in average case duration among services, or whether a surgeon followed himself or another surgeon in the same operating room. Tardiness was affected by expected under-utilized or over-utilized time at the end of the workday and by case duration bias.
Conclusions: Factors associated with the largest numbers of cases had the biggest influence on tardiness. Greater understanding of these factors aided in the development of several mathematical interventions to reduce tardiness in the two surgical suites. These interventions and their applicability for reducing tardiness are described in a companion article. At two surgical suites, tardiness from scheduled start times did not depend on average case duration or prolonged turnovers. Tardiness did depend on the total duration of preceding cases, expected under-utilized or over-utilized time at the end of the day, and case duration bias.