LINKING PARAMETER ESTIMATES DERIVED FROM AN ITEM RESPONSE MODEL THROUGH SEPARATE CALIBRATIONS

Abstract

A regression procedure is developed to link simultaneously a very large number of item response theory (IRT) parameter estimates obtained from a large number of test forms, where each form has been separately calibrated and where forms can be linked on a pairwise basis by means of common items. An application is made to forms in which a two-parameter logistic model is applied to dichotomous items and a general partial credit model is applied to polytomous items.