Learning and Hierarchies in Service Systems
We consider the design of service systems that process tasks with types that are ex ante unknown, and employ servers with different skill sets. We show that the performance loss due to the uncertainty can be significant and that the system’s stability region is dependent on the rate at which information about tasks’ types is generated. Furthermore, we consider endogenizing the servers’ capabilities and explore the problem of jointly optimizing over training and staffing levels and the resource allocation policy. We find that among optimal designs there always exists one with a hierarchical structure, where all tasks are initially routed to the least skilled servers and then progressively move to more skilled ones, if necessary.