Inconsistent Objectives in Operating Room Scheduling

The efficient scheduling of operating room (OR) slates is critical in a hospital setting, especially given OR slates are linked with preoperative and postoperative services. Wait list minimization is a common goal in OR scheduling, one that is broadly defined and can be achieved from many perspectives. Due to the complexity of OR scheduling, and the absence of industrial engineering techniques in healthcare environments, simple rules are often used in scheduling OR slates - typically, the shortest processing time (SPT) rule and the longest processing time (LPT) rule. The SPT and LPT rules, however, have conflicting outcomes in sequencing surgeries. The application of these rules causes confusion in scheduling OR slates. In this paper, we examine wait list minimization from an operations research perspective, explain why SPT and LPT rules are used to achieve this goal, and discuss their conflicting effect on scheduling performance. We also propose a state space with head, body, and tail (SS-HBT) heuristic as an alternative means to achieve this goal. Through case studies, we show that when applied to scheduling OR slates, our SS-HBT heuristic outperforms two well-established heuristics for wait list minimization.