Optimal Queue Design

We study the optimal design of a queueing system when agents' arrival and servicing are governed by a general Markov process. The designer of the system chooses entry and exit rules for agents, their service priority---or queueing discipline---as well as their information, while ensuring that agents have incentives to follow the designer's recommendations not only to join the queue but more importantly to stay in the queue. The optimal mechanism has a cutoff structure----agents are induced to enter up to a certain queue length and no agents are to exit the queue once they enter the queue; the agents on the queue are served according to a first-come-first-served (FCFS) rule; and they are given no information throughout the process beyond the recommendations they receive from the designer. FCFS is also necessary for optimality in a rich domain. We identify a novel role for queueing disciplines in regulating agents' beliefs, and their dynamic incentives, revealing a hitherto unrecognized virtue of FCFS in this regard