Person dimensionality in language test validation

Abstract

In an attempt to extend our knowledge about potential implications of person dimensionality for language test validation, the study reported here was designed: (1) to identify person similarities in a language proficiency testing data set; (2) to attempt to relate such person dimensions to demographic information on the persons so as to provide appropriate labels for the dimensions; and (3) to investigate differential item functioning for the person dimensions identified and labelled. This final focus of the study was intended to reveal whether test items were functioning in an equivalent and valid manner for all person dimensions and, if not, whether there were any discernible patterns of item types that were functioning differentially for particular person dimensions.