Performance characteristics of automated call distribution systems

It is shown that choosing appropriate performance characteristics is crucial to the correct sizing of an automated call distribution (ACD) system. The fraction of rejected calls, which is widely considered as the major performance characteristic, should be replaced by the fraction of served clients. The opportunity to measure the fraction of served clients will arise with the introduction of ISDN and SS7. It is argued that the number of access circuits and ACD systems needs to exceed the number of agents by only approximately 10%. Increasing this percentage further leads to tremendous growth in the waiting time without any further significant increase in the fraction of served clients. It is shown that the performance characteristics of the ACD system are very sensitive to parameters that are mostly defined by the nature of the user´s business, and are not very sensitive to parameters that are defined by human nature