This paper studies service systems with gatekeepers who diagnose a customer problem and then either refer the customer to an expert or attempt treatment. The probability of successful treatment by a gatekeeper decreases as the problem's complexity increases. We determine the optimal staffing...

Optimization models enable organizations to find the best solution and respond to the demand from an uncertain environment and stochastic process promptly and with less engineering effort. This study aims to optimize the number of seasonal agents and customer prioritization needed for a call...

We consider the robust design and control of call center systems with flexible interactive voice response (IVR) systems. In a typical call center equipped with an IVR system, customers are handled first by the IVR system, which is a computerized system that often enables customers to self-serve....

This paper studies outsourcing decisions for a two-level service process in which the first level serves as a gatekeeper for a second level of experts. The objective of the system operator (the client) is to minimize the sum of staffing costs, customer waiting costs, and mistreatment costs due...

In this paper, we analyze the performance of call centers of financial service providers with two levels of support and a time-dependent overflow mechanism. Waiting calls from the front-office queue flow over to the back office, if a waiting-time limit is reached and at least one back-office...

Important features to be included in queueing-theoretic models of the call center operation are multiple servers, impatient customers, time-varying arrival process, and operator’s after-call work (ACW). We propose a fluid approximation technique for the queueing model with these features by...

In this paper we study a challenging call center operation problem. The goal of our analysis is to identify an optimal policy for allocating tasks to agents. As a first step, we discuss promising randomized policies and use stochastic approximation for finding the optimal randomized policy when...

We consider a queueing system where some of the customers are redirected from one queue to the other. We distinguish between those who are redirected and those who exit the system after being served by their service rate. Although it is assumed that all external arrived and services are...