UCL School of Management is delighted to welcome Professor Ricky Roet-Green, University of Rochester to host a research seminar discussing; ‘Foresee the Next Line: Customer Strategies and Information Disclosure in Tandem Queues’

 Abstract:

Many services consist of multiple stages, where each stage requires some waiting before completion. For example, customers who visit the Apple Store join the check-in queue first, and then wait in another queue to be served by the Genius Bar technician. Although customers may observe the queue in front of them, they usually have no information about the waiting situation in the next queue. Our paper aims to examine the impact of queue-length information on customers’ strategic behavior in such systems. We assume a two-stage tandem queueing system, with an admission queue followed by a treatment queue. Customers observe the queue length at arrival to each queue; they may balk or join and might later renege. We first study the fully observable model, in which queue-length information of both queues is available to customers at the time they arrive to the system.  We calculate the equilibrium strategy and show that it is not necessarily a function of the total number of customers in the system. Next, we study the partially observable model, in which customers observe each queue length only at arrival to it, i.e., they do not observe the second queue length when they arrive to the system. Although this is the common practice, it is analytically more challenging. We prove the existence of a threshold equilibrium strategy in this model. For both models, we prove that customers who join the system never renege but may balk when transitioning from one queue to another. To study the value of information in a tandem-queueing setting, we compare the system performance across the fully and partially observable models. We find that in most cases the partially observable model yields higher throughput but lower social welfare compared to the fully observable model.