Call centers with hyperexponential patience modeling

An important feature in call center modeling is the presence of impatient customers. In this paper we show, using real data, that we can realistically model the patience distribution by the hyperexponential distribution. Since the hyperexponential distribution is a mixture of exponential distributions, an analytical Markov chain analysis is performed. A framework is developed in order to compute all kinds of practical service levels. This framework utilizes the recursive relation between the queue lengths at successive service completion epochs. Our approach shows overall better performance compared to current algorithms. Moreover, the computation times are short and our approach can therefore readily be applied in practice.