Refining Square-Root Safety Staffing by Expanding Erlang C

Authors:
A. J. E. M. Janssen;J. S. H. van Leeuwaarden;Bert Zwart
Affiliations:
Eindhoven University of Technology and EURANDOM, 5600 MB Eindhoven, The Netherlands;Eindhoven University of Technology and EURANDOM, 5600 MB Eindhoven, The Netherlands;H. Milton Stewart School of Industrial and Systems Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332
Venue:
Operations Research
Year:
2011

Citing 9
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Abstract

We apply a new corrected diffusion approximation for the Erlang C formula to determine staffing levels in cost minimization and constraint satisfaction problems. These problems are motivated by large customer contact centers that are modeled as an M/M/s queue with s the number of servers or agents. The proposed staffing levels are refinements of the celebrated square-root safety-staffing rule and have the appealing property that they are as simple as the conventional square-root safety-staffing rule. In addition, we provide theoretical support for the empirical fact that square-root safety-staffing works well for moderate-sized systems.