Determining differential item functioning and its effect on the test scores of selected pib indexes, using item response theory techniques

Abstract

The objective of this article is to present the results of an investigation into the item and test characteristics of two tests of the Potential Index Batteries (PIB) in terms of differential item functioning (DIP) and the effect thereof on test scores of different race groups. The English Vocabulary (Index 12) and Spelling Tests (Index 22) of the PIB were analysed for white, black and coloured South Africans. Item response theory (IRT) methods were used to identify items which function differentially for white, black and coloured race groups.

Opsomming
Die doel van hierdie artikel is om die resultate van n ondersoek na die item- en toetseienskappe van twee PIB (Potential Index Batteries) toetse in terme van itemsydigheid en die invloed wat dit op die toetstellings van rassegroepe het, weer te gee. Die Potential Index Batteries (PIB) se Engelse Woordeskat (Index 12) en Spellingtoetse (Index 22) is ten opsigte van blanke, swart en gekleurde Suid-Afrikaners ontleed. Itemresponsteorie (IRT) is gebruik om items te identifiseer wat as sydig (DIP) vir die onderskeie rassegroepe beskou kan word.