Staffing Multiskill Call Centers via Linear Programming and Simulation

• Published in: Management science Vol. 54; no. 2; pp. 310 - 323
• Main Authors: Cezik, Mehmet Tolga, L'Ecuyer, Pierre
• Format: Journal Article
• Language: English
• Published: Linthicum INFORMS 01.02.2008; Institute for Operations Research and the Management Sciences
• Series: Management Science
• Subjects: Algorithms; Business management; Business services; Business studies; Call centers; Call centres; Concavity; Cost control; cutting planes; Employee recruitment; Heuristics; Human resources; Information and communication technologies; integer programming; Integers; Linear programming; Management science; Mathematical vectors; Operations research; Optimal solutions; optimization by simulation; Personnel management; Programming; Recruiting; Scheduling; Service industry; Simulation; skill-based routing; Staffing; Studies; subgradient cuts; Technology application; Workforce planning; United States
• ISSN: 0025-1909; 1526-5501
• DOI: 10.1287/mnsc.1070.0824

We study an iterative cutting-plane algorithm on an integer program for minimizing the staffing costs of a multiskill call center subject to service-level requirements that are estimated by simulation. We solve a sample average version of the problem, where the service levels are expressed as functions of the staffing for a fixed sequence of random numbers driving the simulation. An optimal solution of this sample problem is also an optimal solution to the original problem when the sample size is large enough. Several difficulties are encountered when solving the sample problem, especially for large problem instances, and we propose practical heuristics to deal with these difficulties. We report numerical experiments with examples of different sizes. The largest example corresponds to a real-life call center with 65 types of calls and 89 types of agents (skill groups).