A practice-oriented overview of call center workforce planning

We give an overview of the practice and science of call center workforce planning, where we evaluate the commonly used methods by their quality and the theory by its applicability. As such this paper is useful for developers and consultants interested in the background and advanced methodology of workforce management, and for researchers interested in practically relevant science.

[1]  Guodong Pang,et al.  A Logarithmic Safety Staffing Rule for Contact Centers with Call Blending , 2015, Manag. Sci..

[2]  Steven Nahmias.  Queues with Impatient Customers , 2011 .

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

[4]  Edieal J. Pinker,et al.  Call Center Outsourcing Contracts Under Information Asymmetry , 2008, Manag. Sci..

[5]  Paul D. Feigin.  Analysis of Customer Patience in a Bank Call Center , 2006 .

[6]  Haipeng Shen,et al.  Parametric Forecasting and Stochastic Programming Models for Call-Center Workforce Scheduling , 2015, Manuf. Serv. Oper. Manag..

[7]  Oualid Jouini,et al.  Adaptive threshold policies for multi-channel call centers , 2015 .

[8]  Amy R. Ward,et al.  Fair Dynamic Routing in Large-Scale Heterogeneous-Server Systems , 2010, Oper. Res..

[9]  E. Kaplan,et al.  Nonparametric Estimation from Incomplete Observations , 1958 .

[10]  George Athanasopoulos,et al.  Forecasting: principles and practice , 2013 .

[11]  Nigel Meade,et al.  Forecasting call frequency at a financial services call centre , 2002, J. Oper. Res. Soc..

[12]  L. Brown,et al.  Hazard rate estimation for call center customer patience time , 2020, IISE Trans..

[13]  James R. Luedtke,et al.  Mixed-Integer Rounding Enhanced Benders Decomposition for Multiclass Service-System Staffing and Scheduling with Arrival Rate Uncertainty , 2017, Manag. Sci..

[14]  Sandjai Bhulai,et al.  Simple Methods for Shift Scheduling in Multiskill Call Centers , 2008, Manuf. Serv. Oper. Manag..

[15]  Yves Dallery,et al.  Call Centers with Delay Information: Models and Insights , 2011, Manuf. Serv. Oper. Manag..

[16]  Constantinos Maglaras,et al.  Decision , Risk and Operations Working Papers Series Contact Centers with a CallBack Option and Real-Time Delay Information , 2004 .

[17]  Jean-Philippe Vial,et al.  Distributionally robust workforce scheduling in call centres with uncertain arrival rates , 2013, Optim. Methods Softw..

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

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

[20]  James W. Taylor,et al.  A Comparison of Univariate Time Series Methods for Forecasting Intraday Arrivals at a Call Center , 2008, Manag. Sci..

[21]  J. Michael Harrison,et al.  Design and Control of a Large Call Center: Asymptotic Analysis of an LP-Based Method , 2006, Oper. Res..

[22]  J. Michael Harrison,et al.  A Method for Staffing Large Call Centers Based on Stochastic Fluid Models , 2005, Manuf. Serv. Oper. Manag..

[23]  Terry P. Harrison,et al.  A stochastic programming model for scheduling call centers with global Service Level Agreements , 2010, Eur. J. Oper. Res..

[24]  Ward Whitt,et al.  Wait-Time Predictors for Customer Service Systems with Time-Varying Demand and Capacity , 2011, Oper. Res..

[25]  Ward Whitt,et al.  Engineering Solution of a Basic Call-Center Model , 2005, Manag. Sci..

[26]  Tevfik Aktekin,et al.  Bayesian Analysis of Abandonment in Call Center Operations , 2014 .

[27]  Brad Cleveland.  Call Center Management on Fast Forward: Succeeding in Today's Dynamic Customer Contact Environment , 2006 .

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

[29]  Vinayak Deshpande,et al.  Don't Call Us, We'll Call You: An Empirical Study of Caller Behavior Under a Callback Option , 2020, Manag. Sci..

[30]  Oualid Jouini,et al.  A Simple Solution for Optimizing Weekly Agent Scheduling in a Multi-Skill Multi-Channel Contact Center , 2019, 2019 Winter Simulation Conference (WSC).

[31]  Pierre L'Ecuyer,et al.  Dynamic Call Center Routing Policies Using Call Waiting and Agent Idle Times , 2014, Manuf. Serv. Oper. Manag..

[32]  Itay Gurvich,et al.  Staffing Call Centers with Uncertain Demand Forecasts: A Chance-Constrained Optimization Approach , 2010, Manag. Sci..

[33]  Avishai Mandelbaum,et al.  Statistical Analysis of a Telephone Call Center , 2005 .

[34]  Ward Whitt,et al.  The Impact of Delay Announcements in Many-Server Queues with Abandonment , 2009, Oper. Res..

[35]  Alexander L. Stolyar,et al.  Scheduling Flexible Servers with Convex Delay Costs: Heavy-Traffic Optimality of the Generalized cµ-Rule , 2004, Oper. Res..

[36]  Noah Gans,et al.  Call-Routing Schemes for Call-Center Outsourcing , 2007, Manuf. Serv. Oper. Manag..

[37]  Jun Luo,et al.  Staffing and Control of Instant Messaging Contact Centers , 2013, Oper. Res..

[38]  Benjamin Legros.  Reservation, a tool to reduce the balking effect and the probability of delay , 2017, Oper. Res. Lett..

[39]  Oualid Jouini,et al.  Call centers with hyperexponential patience modeling , 2013 .

[40]  Constantinos Maglaras,et al.  On Customer Contact Centers with a Call-Back Option: Customer Decisions, Routing Rules, and System Design , 2004, Oper. Res..

[41]  Spyros Makridakis,et al.  Forecasting, planning, and strategy for the 21st century , 1990 .

[42]  Refik Soyer,et al.  Modeling and Analysis of Call Center Arrival Data: A Bayesian Approach , 2008, Manag. Sci..

[43]  Avishai Mandelbaum,et al.  Workload forecasting for a call center: Methodology and a case study , 2009, 1009.5741.

[44]  Avishai Mandelbaum,et al.  The impact of customers’ patience on delay and abandonment: some empirically-driven experiments with the M/M/n + G queue , 2004, OR Spectr..

[45]  Illah R. Nourbakhsh,et al.  Staff scheduling for inbound call centers and customer contact centers , 2002, AAAI/IAAI.

[46]  Oualid Jouini,et al.  Optimal scheduling in call centers with a callback option , 2016, Perform. Evaluation.

[47]  J. Reed,et al.  The G/GI/N queue in the Halfin–Whitt regime , 2009, 0912.2837.

[48]  Stefan Karlsson,et al.  Forecasting incoming call volumes in call centers with recurrent Neural Networks , 2016 .

[49]  Sandjai Bhulai,et al.  A Simple Staffing Method for Multiskill Call Centers , 2008, Manuf. Serv. Oper. Manag..

[50]  Alexander L. Stolyar,et al.  Multiclass multiserver queueing system in the Halfin–Whitt heavy traffic regime: asymptotics of the stationary distribution , 2012, Queueing Syst. Theory Appl..

[51]  Ger Koole,et al.  Optimal Shift Scheduling with a Global Service Level Constraint , 2003 .

[52]  Sandjai Bhulai,et al.  A queueing model for call blending in call centers , 2003, IEEE Trans. Autom. Control..

[53]  Noah Gans,et al.  A Call-Routing Problem with Service-Level Constraints , 2003, Oper. Res..

[54]  Ward Whitt,et al.  Heavy-Traffic Limits for Queues with Many Exponential Servers , 1981, Oper. Res..

[55]  Oualid Jouini,et al.  Call centers with a postponed callback offer , 2017, OR Spectr..

[56]  P. Kolesar,et al.  The Pointwise Stationary Approximation for Queues with Nonstationary Arrivals , 1991 .

[57]  Che-Lin Su,et al.  Impact of Delay Announcements in Call Centers: An Empirical Approach , 2017, Oper. Res..

[58]  Pierre L'Ecuyer,et al.  Modeling and forecasting call center arrivals: A literature survey and a case study , 2015 .

[59]  D. Norman.  THE PSYCHOLOGY OF WAITING LINES , 2008 .

[60]  Robert D. van der Mei,et al.  On the estimation of the true demand in call centers with redials and reconnects , 2015, Eur. J. Oper. Res..

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

[62]  Itay Gurvich,et al.  Overflow Networks: Approximations and Implications to Call Center Outsourcing , 2012, Oper. Res..

[63]  Fikri Karaesmen,et al.  Call Center Outsourcing Contract Analysis and Choice , 2008, Manag. Sci..

[64]  Armann Ingolfsson,et al.  Markov chain models of a telephone call center with call blending , 2007, Comput. Oper. Res..

[65]  N. Shimkin,et al.  The c / Rule for Many-Server Queues with Abandonment , 2009 .

[66]  George B. Dantzig,et al.  Letter to the Editor - A Comment on Edie's "Traffic Delays at Toll Booths" , 1954, Oper. Res..

[67]  Oualid Jouini,et al.  Staffing a call center with uncertain non-stationary arrival rate and flexibility , 2012, OR Spectr..

[68]  Amy R. Ward,et al.  Blind Fair Routing in Large-Scale Service Systems with Heterogeneous Customers and Servers , 2013, Oper. Res..

[69]  Pierre L'Ecuyer,et al.  Two-stage chance-constrained staffing with agent recourse for multi-skill call centers , 2016, 2016 Winter Simulation Conference (WSC).

[70]  Avishai Mandelbaum,et al.  Call Centers with Impatient Customers: Many-Server Asymptotics of the M/M/n + G Queue , 2005, Queueing Syst. Theory Appl..

[71]  Yves Dallery,et al.  A flexible architecture for call centers with skill-based routing , 2012 .

[72]  Oualid Jouini,et al.  On the scheduling of operations in a chat contact center , 2019, Eur. J. Oper. Res..

[73]  Tava Lennon Olsen,et al.  Service-Level Agreements in Call Centers: Perils and Prescriptions , 2008, Manag. Sci..

[74]  Pierre L'Ecuyer,et al.  Staffing Multiskill Call Centers via Linear Programming and Simulation , 2008, Manag. Sci..

[75]  Shane G. Henderson,et al.  Optimizing Call Center Staffing Using Simulation and Analytic Center Cutting-Plane Methods , 2008, Manag. Sci..

[76]  Sandjai Bhulai,et al.  Flexible Staffing for Call Centers with Non-stationary Arrival Rates , 2017 .

[77]  Raik Stolletz,et al.  Service-Level Variability of Inbound Call Centers , 2012, Manuf. Serv. Oper. Manag..

[78]  Philippe Chevalier,et al.  Overflow analysis and cross-trained servers , 2003 .

[79]  Tolga Tezcan,et al.  Routing and Staffing in Customer Service Chat Systems with Impatient Customers , 2014, Oper. Res..

[80]  Yves Dallery,et al.  Analysis of the Impact of Team-Based Organizations in Call Center Management , 2008, Manag. Sci..

[81]  Tolga Tezcan,et al.  Approximations for Chat Service Systems Using Many-Server Diffusion Limits , 2016, Math. Oper. Res..

[82]  Zuohua Ding,et al.  Forecasting Emergency Calls With a Poisson Neural Network-Based Assemble Model , 2019, IEEE Access.

[83]  Anton Braverman,et al.  Steady-State Analysis of the Join-the-Shortest-Queue Model in the Halfin-Whitt Regime , 2018, Math. Oper. Res..

[84]  Amy R. Ward,et al.  Threshold Routing to Trade Off Waiting and Call Resolution in Call Centers , 2014, Manuf. Serv. Oper. Manag..

[85]  Pierre L'Ecuyer,et al.  A normal copula model for the arrival process in a call center , 2012, Int. Trans. Oper. Res..

[86]  Edwin L. Crow.  The mean deviation of the Poisson distribution , 1958 .

[87]  Tevfik Aktekin,et al.  Call center service process analysis: Bayesian parametric and semi-parametric mixture modeling , 2014, Eur. J. Oper. Res..

[88]  Robert A. Shumsky,et al.  Routing and Staffing in Large Call Centers with Specialized and Fully Flexible Servers , 2004 .

[89]  Serguei Netessine,et al.  When Does the Devil Make Work? An Empirical Study of the Impact of Workload on Worker Productivity , 2014, Manag. Sci..

[90]  Ward Whitt,et al.  Staffing a Call Center with Uncertain Arrival Rate and Absenteeism , 2006 .

[91]  Ward Whitt,et al.  Are Call Center and Hospital Arrivals Well Modeled by Nonhomogeneous Poisson Processes? , 2014, Manuf. Serv. Oper. Manag..

[92]  Jonathan Weinberg,et al.  Bayesian Forecasting of an Inhomogeneous Poisson Process With Applications to Call Center Data , 2007 .

[93]  Ward Whitt,et al.  Real-Time Delay Estimation Based on Delay History , 2009, Manuf. Serv. Oper. Manag..

[94]  Shane G. Henderson,et al.  Service system planning in the presence of a random arrival rate , 2004 .

[95]  Michel Gendreau,et al.  Optimizing daily agent scheduling in a multiskill call center , 2010, Eur. J. Oper. Res..

[96]  Pierre L'Ecuyer,et al.  Forecasting Call Center Arrivals: Fixed-Effects, Mixed-Effects, and Bivariate Models , 2012, Manuf. Serv. Oper. Manag..

[97]  R. Atar.  Scheduling control for queueing systems with many servers: asymptotic optimality in heavy traffic , 2005, math/0602526.

[98]  J. Michael Harrison,et al.  Dynamic Scheduling of a Multiclass Queue in the Halfin-Whitt Heavy Traffic Regime , 2004, Oper. Res..

[99]  David Y. Sze,et al.  A Queueing Model for Telephone Operator Staffing , 2016 .

[100]  Pierre L'Ecuyer,et al.  Modeling and simulation of call centers , 2005, Proceedings of the Winter Simulation Conference, 2005..