Most companies nowadays have call centers, or hire specialized firms to handle their communications with customers through call centers. As such there is an enormous financial interest in call centers. Current trends are towards an increase in size and in complexity.
The management of call centers can be split in two parts. Issues related to the effectiveness of the services offered by the call center require ICT and product-related skills. The efficiency is for a considerable part the domain of mathematics. Because the costs are dominated by personnel costs, this amounts to an efficient use of the workforce. The basis of workforce management in call centers is the well-known Erlang formula : it allows one to calculate the waiting time distribution under given load and number of servers. It is used in call centers to calculate the number of servers needed to meet the required waiting time objectives. From this daily requirements are calculated which form the basis of the agent schedules. The research projects that we discuss in the next section can all be seen as extensions of the Erlang formula.
For an extensive overview of call center research, see Gans et al. .