Call-type dependence in multiskill call centers

The effect on multiskill call-center performance of pooling dependent call types is investigated. For this purpose, a copula-based modeling approach is used to provide multivariate models that take into account the call types’ asymmetric dependence structures found in empirical data. Then, the realistic input models of the call-type-dependent arrival processes are used in a simulation study to explore the sensitivity of the pooling decision to this dependence. We find that the widely used assumption of independence, as well as the misspecification of the dependence structure, can lead to substantial misestimation of call-center performance. This demonstrates the importance of modeling call-type dependence in stochastic simulation studies of call centers. We also show, through case studies, that pooling two asymmetric left-tail-dependent call types is more likely to lead to low agents occupancy; whereas the presence of right-tail dependence structure increases the risk of service-level shortfall. This work provides new managerial insights to improve decision making in determining which call types to merge in the same pool in multiskill call centers.

[1]  M. Sklar.  Fonctions de repartition a n dimensions et leurs marges , 1959 .

[2]  B. Brorsen,et al.  Forecasting Hourly Peak Call Volume for a Rural Electric Cooperative Call Center , 2012 .

[3]  Pravin K. Trivedi,et al.  Copula Modeling: An Introduction for Practitioners , 2007 .

[4]  Stefan Helber,et al.  Performance analysis of an inbound call center with skills-based routing , 2004, OR Spectr..

[5]  Pierre L'Ecuyer,et al.  An Object-Oriented Random-Number Package with Many Long Streams and Substreams , 2002, Oper. Res..

[6]  P. Embrechts,et al.  Correlation and Dependency in Risk Management , 2002 .

[7]  N. M. vanDijk,et al.  To Pool or Not to Pool in Call Centers , 2008 .

[8]  Pierre L'Ecuyer,et al.  A Java library for simulating contact centers , 2005, Proceedings of the Winter Simulation Conference, 2005..

[9]  P. Embrechts,et al.  Chapter 8 – Modelling Dependence with Copulas and Applications to Risk Management , 2003 .

[10]  Avishai Mandelbaum,et al.  Telephone Call Centers: Tutorial, Review, and Research Prospects , 2003, Manuf. Serv. Oper. Manag..

[11]  Philippe Chevalier,et al.  Optimizing the Staffing and Routing of Small‐Size Hierarchical Call Centers , 2008 .

[12]  Jun Yan,et al.  Enjoy the Joy of Copulas: With a Package copula , 2007 .

[13]  P. Embrechts,et al.  Risk Management: Correlation and Dependence in Risk Management: Properties and Pitfalls , 2002 .

[15]  Zeynep Akşin,et al.  The Modern Call Center: A Multi‐Disciplinary Perspective on Operations Management Research , 2007 .

[16]  W. David Kelton,et al.  Representing and generating uncertainty effectively , 2007, 2007 Winter Simulation Conference.

[17]  R. Nelsen.  An Introduction to Copulas (Springer Series in Statistics) , 2006 .

[18]  Ger Koole,et al.  Managing uncertainty in call centres using Poisson mixtures , 2001 .

[19]  Wallace J. Hopp,et al.  Pooling strategies for call center agent cross-training , 2009 .

[20]  W. David Kelton,et al.  Numerical Methods for Realizing Nonstationary Poisson Processes with Piecewise-Constant Instantaneous-Rate Functions , 2006, Simul..

[21]  Thorsten Rheinländer.  Risk Management: Value at Risk and Beyond , 2003 .

[22]  O. Zeynep Akşin,et al.  A REVIEW OF WORKFORCE CROSS-TRAINING IN CALL CENTERS FROM AN OPERATIONS MANAGEMENT PERSPECTIVE , 2007 .

[23]  Ward Whitt,et al.  A Staffing Algorithm for Call Centers with Skill-Based Routing , 2005, Manuf. Serv. Oper. Manag..

[24]  Mahvareh Ahghari,et al.  Benefits of cross-training in a skill-based routing contact center with priority queues and impatient customers , 2009 .

[25]  C. Genest,et al.  The Advent of Copulas in Finance , 2009 .

[26]  Pierre L'Ecuyer,et al.  Modeling Daily Arrivals to a Telephone Call Center , 2003, Manag. Sci..

[27]  Pierre L'Ecuyer,et al.  Simulation in Java with SSJ , 2005, Proceedings of the Winter Simulation Conference, 2005..

[28]  YiHao Lai.  Does Asymmetric Dependence Structure Matter? A Value-at-Risk View , 2008 .

[29]  Pierre L'Ecuyer,et al.  Customer relations management: call center operations: modelling and simulation of a telephone call center , 2003, WSC '03.