【Topic】QED Services: Quality- and Efficiency-Driven Call Centers

【Speaker】Professor Avishai (Avi) Mandelbaum

【Time】2008-10-31, 10:00-11:00 am

【Venue】Room 453, Weilun Building, School of Economics and Management,

Tsinghua University

【Abstract】Through examples of Service Operations, with a focus on Telephone Call Centers, I review empirical findings that motivate or are motivated by (or both) interesting research questions. These findings give rise to features that are prerequisites for useful service models, for example customers’ (im)patience, time-varying demand, heterogeneity of customers and servers, over-dispersion in Poisson arrivals, generally-distributed (as opposed to exponential) service- and patience-durations, and more. Empirical analysis also enables validation of existing models and protocols, either supporting or refuting their relevance and robustness. The mathematical framework for my models is asymptotic queueing theory, where limits are taken as the number of servers increases indefinitely, in a way that maintains a delicate balance against the offered-load. Asymptotic analysis reveals an operational regime that achieves, under already moderate scale, remarkably high levels of both service quality and efficiency. This is the QED Regime, discovered by Erlang and characterized by Halfin & Whitt. (QED = Quality- and Efficiency-Driven).

【About the speaker】Prof. Mandelbaum has a B.Sc. in Mathematics and Computer Science and an M.A. in Statistics, both summa cum laude from Tel-Aviv University. His Ph.D. is in Operations Research, from Cornell University. After graduation, in 1983, he joined the Graduate School of Business at Stanford University. He left the U.S.A., in 1991, to assume a position at the Technion. Prof. Mandelbaum has been an associate editor of the leading journals in his field, in particular Math. of OR, Management Science and QUESTA (Queueing Theory). Prof. Mandelbaum’s teaching has been acknowledged by Technion prizes, in particular the Technion Excellence in Teaching Award for the course Service Engineering. His research has focused on stochastic models (analysis, asymptotics, control) and statistics, with applications to service systems, notably tele-services (eg. telephone call centers) and healthcare (eg. patients flow through emergency departments). His research has been acknowledged by prizes, for example the inaugural Markov Lecture of the Applied Probability Society, INFORM 2005. Prof. Mandelbaum is the founder and director of the Technions SEE Center/Laboratory (SEE = Service Enterprise Engineering), which serves as a focal point for service research at the Technion, as well as a data repository for call centers and hospitals.