A call center is a service network in which agents provide telephone-based services. Customers that seek such services may be delayed in tele-queues, which are invisible to them.

The talk summarizes an analysis of a unique record of call center operations. The data comprise a complete operational history of a small banking call center, call by call, over a full year. Taking the perspective of queueing theory, we decompose the service process into three fundamental components: arrivals, waiting times, and service durations. Each component involves different basic mathematical structures and requires a different style of statistical analysis. Some of the key results will be sketched, along with descriptions of the varied techniques required.

In conclusion we survey how the characteristics deduced from the statistical analyses form the building blocks for theoretically interesting and practically useful mathematical models for call center operations.

This reports on joint work with Larry Brown, Linda Zhao and Noah Gans from Wharton, and Avishai Mandelbaum, Anat Sakov and Sergey Zeltyn from Technion (Israel).