Fit of Responses to the Polytomous Rasch Model

Abstract

One type of fit which examines the consistency of the data with the model begins with the difference between the observed and expected score at the person–item response level, given the parameter estimates. Then a fit statistic can be obtained at both the person (person fit-residualPerson fit-residual) and item (item fit-residualItem fit-residual) level following a parallel sequence of steps.