A Characterization of Optimal Queueing Regimes
Marco Scarsini, Eran Shmaya
TL;DR
The paper characterizes universally optimal queueing regimes for an M/M/1 with strategic entry decisions, introducing an abstract regime framework and a necessary-and-sufficient condition for universality: a new arrival may join at the back of the queue only if the past could not have supported a larger queue, with preemption emerging as essential in some cases. It shows Hassin's sufficient condition is not necessary by including the priority-slots regime and constructs a new universally optimal regime using a scoring priority mechanism. The results connect social-optimum thresholds with equilibrium behavior under any parameter set, providing design principles for parameter-free queue protocols that achieve welfare optimality across settings. This advances the theory of strategic queues by formalizing universal optimality and delivering concrete regime examples and proofs that unify prior insights on FCFS, preemption, and priority-based schemes. The findings have implications for capacity design and regulatory policies in service systems where requester behavior adapts to incentives and externalities.
Abstract
We consider an M/M/1 queueing model where customers can strategically decide to enter or leave the queue. We characterize the class of queueing regimes such that, for any parameters of the model, the socially efficient behavior is an equilibrium outcome.
