Investigating Group Invariance of Equating Results

Abstract

In this study, it was investigated that Item Response Theory (IRT) equating results whether or not group invariant. Group invariance of equating functions means that equating is same for everyone in the population. The raw scores which were taken from 9th grade 2009 ÖBBS D form of Social Sciences were equated to 2009 ÖBBS B form of Social Sciences with IRT true-and observed- score equating methods. Equating study was conducted with using equivalent groups design. The subgroups were generated with regard to examinees’ self-perceived competence in geography and history lessons. The results indicated that under the both IRT truescore and observed-score equating methods, equating results were group sensitive.