Using item response theory in test score equating

Abstract

In this chapter, the theoretical advantages that have been offered for using item response theory (IRT) in the test equating process are discussed. In addition, IRT equating research is reviewed with regard to certain important equating issues addressed in this research. These issues fall into four general categories: (1) population invariance of equating results and sample selection in equating, (2) properties of linking items used in anchor test equatings, (3) further examinations of the use of IRT in the vertical equating of tests, and (4) robustness of IRT equating to violations of underlying IRT model assumptions. The chapter concludes with a number of practical suggestions to guide researchers interested in IRT for test equating purposes.