On the psychological cost of waiting in queues

Cenk Kocas, Purdue University


In this research, building on the cognitive stress theories of waiting, we develop and test a model of the psychological cost of waiting in lines. In our model, we consider how the length of the queue, the mean waiting time, and the uncertainty in waiting time affect the accumulation of stress. We carry out an empirical test of the key premises of our total expected stress (TES) model and find that they are supported. As per our model, frequent positive feedback on the estimate of the remaining waiting time can improve customer satisfaction with the waiting process. Customer frustration with waiting increases during extended waits between queue movements. Customer frustration with waiting is exacerbated when customers are not processed in an equitable and socially just manner. Further, given the convex relationship between the accumulated stress and waiting time in a state, losses loom larger than gains. As an application of our model, we compare the total expected stress accumulated while waiting in a single-line-multiple-server queue with that accumulated while waiting in a multiple-line-multiple-server system. This allows us, for example, to compare the psychological cost of waiting at fast food chains such as Wendy's, Taco Bell, and Burger King which use the single line design with the corresponding cost of waiting in a multiple line system employed by chains such as McDonald's and Arby's. We find that the total expected stress is lower in the single queue system than in the multiple queue design. Banks, of late, increasingly seem to prefer the single line design. To this end, we address the question: is it always beneficial to combine queues? We also apply our model to the management of customer waiting experiences in checkout lanes at supermarkets and mass merchandiser outlets. In this setting, our focus is on segmenting customers into service classes and serving them through express and regular lanes. Our TES model allows a simultaneous consideration of all three queue characteristics to examine when the conversion of one or more regular lanes to express lanes will lead to lower total expected stress per customer.




Kalwani, Purdue University.

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