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Service times in call centers: Agent heterogeneity and learning with some operational consequences

Noah Gans, Nan Liu, Avishai Mandelbaum, Haipeng Shen, and Han Ye

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Telephone call centers are data-rich environments that, until recently, have not received sustained attention from academics. For about a decade now, we have been fortunate to work with our colleague, mentor and friend, Larry Brown, on the collection and analysis of large call-center datasets. This work has provided many fascinating windows into the world of call-center operations, stimulating further research and affecting management practice. Larry’s inexhaustible curiosity and creativity, sharp insight and unique technical power, have continuously been an inspiration to us. We look forward to collaborating with and learning from him on many occasions to come.

In this paper, we study operational heterogeneity of call center agents. Our proxy for heterogeneity is agents’ service times (call durations), a performance measure that prevalently “enjoys" tight management control. Indeed, managers of large call centers argue that a 1-second increase/decrease in average service time can translate into additional/reduced operating costs on the order of millions of dollars per year.

We are motivated by an empirical analysis of call-center data, which identifies both short-term and long-term factors associated with agent heterogeneity. Operational consequences of such heterogeneity are then illustrated via discrete event simulation. This highlights the potential benefits of analyzing individual agents’ operational histories. We are thus naturally led to a detailed analysis of agents’ learning-curves, which reveals various learning patterns and opens up new research opportunities.

Chapter information

James O. Berger, T. Tony Cai and Iain M. Johnstone, eds., Borrowing Strength: Theory Powering Applications – A Festschrift for Lawrence D. Brown (Beachwood, Ohio, USA: Institute of Mathematical Statistics, 2010), 99-123

First available in Project Euclid: 26 October 2010

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Copyright © 2010, Institute of Mathematical Statistics


Gans, Noah; Liu, Nan; Mandelbaum, Avishai; Shen, Haipeng; Ye, Han. Service times in call centers: Agent heterogeneity and learning with some operational consequences. Borrowing Strength: Theory Powering Applications – A Festschrift for Lawrence D. Brown, 99--123, Institute of Mathematical Statistics, Beachwood, Ohio, USA, 2010. doi:10.1214/10-IMSCOLL608.

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