“Scheduling Customer Arrivals with Overbooking in Service Systems with No-Shows” by Professor Michael PINEDO
Professor Michael PINEDO
Julius Schlesinger Professor of Operations Management
Leonard N. Stern School of Business
New York University
We analyze a discrete multi-server queueing model for scheduling customer arrivals under no-shows. Customers have different waiting cost coefficients and different no-show rates, reflecting their type and their history in attending scheduled appointments respectively. The challenge is to assign customers to time slots so that the service system utilizes its resources efficiently, and customers enjoy short waiting times. Theoretical and heuristic guidelines are provided for the effective practice of appointment overbooking to offset no-shows.
For the case of heterogeneous customers, we show structural properties of optimal schedules and we introduce a new sequencing rule. When customers come from a homogeneous pool, recursive expressions for the performance measures of interest are derived and we provide an upper bound for the optimal overbooking level. Our extensive numerical experiments reveal further properties and patterns that appear in the optimal solution, and motivate the development of two very well performing and computationally inexpensive heuristic solutions. Moreover, our analysis demonstrates the benefits of resource-pooling in containing operational costs and increasing customer throughput.