Methods for Summarizing the Rasch Model Coefficients

The application of the Rasch model to measure the Quality and Customer Satisfaction of a service is possible only for a single dimension of the service. But we know that the Quality and Customer Satisfaction of a service are a compound of more than one dimension. In such a case the Rasch method cannot be applied. As it is well known, the one dimension Rasch model supplies two graduated lists: the first is about subject satisfaction and the second concerns item quality. If there are K service dimensions and if the Rasch model is applied to each of them, K different graduated lists of subject satisfaction for the n individuals are obtained. The aim of this work is to define an overall individual satisfaction measure obtained as linear combination of the K subject graduated lists, with weights estimated in two different ways, for different hypothesis. We have shown that these two methods are consistent.