Ward Whitt


801D Schapiro (CEPSR)
Mail Code 4704

Tel(212) 854-7255
Fax(212) 854-8103

Ward Whitt creates models of congestion (queues), and methods for analyzing those models, used to design and manage telecommunication, manufacturing, computer, and service systems.  This research focus evolved during Whitt’s 25 years at Bell Labs and AT&T Labs before joining the Columbia faculty in 2002.  

Research Interests

Probability models of congestion (queues) and their applications to service, telecommunication, manufacturing and computer systems; analyzing queues with time-varying arrival rates and complex stochastic dependence approximate analysis of complex systems, via asymptotic methods; computer simulation and numerical transform inversion.

Research Areas

His recent work has focused on data-generated models for dynamic resource allocation in service systems such as telephone call centers and hospital emergency departments. A main theme has been developing tractable approximations through asymptotic methods. In addition to developing new asymptotic results, he has developed and applied numerical methods involving computer simulation, numerical transform inversion, and robust optimization.

Of particular interest to Whitt today is the challenge of creating and analyzing non-Markov nonstationary data-driven stochastic queueing models commonly arising in service systems when the arrival rate varies strongly over time and the service times have non-exponential distributions.

Whitt received an AB in mathematics from Dartmouth College in 1964 and a PhD in operations research from Cornell University in 1969. He was on the Yale faculty in 1969-1977; at Bell Labs in 1977-1996; at AT&T Labs in 1996-2002; and joined the Columbia Faculty in 2002.  He has been active in the Institute for Operations Research and the Management Sciences (INFORMS) and its Applied Probability Society. 


  • Wai T. Chang Professor, industrial engineering and operations research (IEOR), Columbia University, 2007–
  • Professor of IEOR, Columbia University, 2002-
  • Technical Leader and AT&T Fellow, AT&T Labs, 1996-2002
  • Member of Technical Staff, Bell Labs, 1977-1996
  • Associate professor of administrative sciences and statistics, Yale University, 1973-1977
  • Assistant professor of administrative sciences, Yale University, 1969-1973
  • Visiting assistant professor of operations research, Stanford University, 1968-1969


  • Institute of Mathematical Statistics (IMS)
  • Institute for Operations Research and the Management Sciences (INFORMS)


  • INFORMS Manufacturing and Service Operation Management Fellow, 2012
  • INFORMS Saul Gass Expository Writing Award, 2011
  • Columbia SEAS Alumni Association Faculty Teaching Award, 2007
  • INFORMS Frederick Lanchester Best Publication Prize (2002 book), 2003
  • INFORMS Inaugural Fellow, 2002
  • INFORMS John von Neumann Theory Prize, 2001
  • AT&T Fellow, 1997
  • National Academy of Engineering, 1996


  • D. L. Iglehart and W. Whitt, “Multiple Channel Queues in Heavy Traffic I,” Advances in Applied Probability 2 150-177 (1970).
  • S. Halfin and W. Whitt, “Heavy-Traffic Limits for Queues with Many Exponential Servers,” Operations Research 29 (3) 567-588 (1981).
  • W. Whitt, “The Queueing Network Analyzer,” Bell System Technical Journal 62 2779-2815 (1983).
  • K. Sriram and W. Whitt, “Characterizing Superposition Arrival Processes in Packet Multiplexers for Voice and Data,” IEEE Journal on Selected Areas in Communications SAC-4 (6) 833-846 (1986).
  • W. Whitt, “Planning Queueing Simulations,” Management Science 35 (11) 1341-1366 (1989).
  • J. Abate and W. Whitt, “The Fourier-Series Method for Inverting Transforms of Probability Distributions,” Queueing Systems 10 (1) 5-88 (1992).
  • P.  W. Glynn and W. Whitt, “Logarithmic Asymptotics for Steady-State Tail Probabilities in a Single-Server Queue,” Studies in Applied Probability, Papers in Honour of Lajos Takacs, J. Galambos and J. Gani (eds.), Applied  Probability Trust, Sheffield, England, 131--156 (1994).
  • G. L. Choudhury, K. K. Leung, “Calculating Normalization Constants of Closed Queueing Networks by Numerically Inverting Their Generating Functions,” Journal of the Association for Computing Machinery, 42 935-970 (1995).
  • O. B. Jennings, A. Mandelbaum, W. A. Massey and W. Whitt, “Server Staffing to Meet Time-Varying Demand, Management Science 42 (10) 1383-1394 (1996).
  • W. Whitt, Stochastic-Process Limits, Springer, New York, 2002, 602 pages.
  • Others: http://www.columbia.edu/~ww2040/allpapers.html