Practical scheduling for call center operations

• Published in: Omega (Oxford) 2011-10, Vol.39 (5), p.550-557
• Main Author: Dietz, Dennis C.
• Format: Article
• Language: English
• Subjects: Applied sciences; Call centers; Exact sciences and technology; Firm modelling; Markov analysis; Mathematical programming; Operational research and scientific management; Operational research. Management science; Operations management; Quadratic programming; Queueing; Queueing Quadratic programming Scheduling Operations management; Queuing theory; Queuing theory. Traffic theory; Reliability theory. Replacement problems; Resource allocation; Scheduling; Studies; Workforce planning
• ISSN: 0305-0483; 1873-5274
• DOI: 10.1016/j.omega.2010.12.001

A practical spreadsheet-based scheduling method is developed to determine the optimal allocation of service agents to candidate tour types and start times in an inbound call center. A stationary Markovian queueing model with customer abandonment is employed to determine required staffing levels for a sequence of time intervals with varying call volumes, handling times, and relative agent availabilities. These staffing requirements populate a quadratic programming model for determining the distribution of agent tours that will maximize the fraction of offered calls beginning service within a target response time, subject to side constraints on tour type quantities. The optimal distribution is scaled to reflect the total number of scheduled agents, and a near-optimal integer solution is derived using rounding thresholds found by successive one-dimensional searches. This novel approach has been successfully implemented in large service centers at Qwest Communications and could easily be adapted to other operational environments.