Determining the differential item functioning of non-verbal intelligence test using item response theory in Rivers State

Abstract

The study investigated the Differential Item Functioning of Non-Nérbal Intelligence Test using Item Response theory. The study adopted non-experimental research design. The population of the study consisted of445,231 Basic 5 pupils in public and private primary schools in Rivers East Senatorial District aged 9 years in the 2019/2020 academic session. The sample of the study comprised 800 pupils drawn through multi-stage procedure. The instrument for data collection was a non-verbal intelligence test standardized by the researcher in 2007. The instrument contained four sections: Figure Classification, Figure Analogies, Figure Synthesis and Matrices. Ruder-Richardson (K-R20) was used in determining the reliability of the instrument. The instrument yielded reliability coefficient of 0.71, 0.75, 0.70 and 0.73 respectively. Item Response Theory Patient Outcome (IRTPRO) was used in determining differential item functioning using method of Item Response Theory. The result of this study showed that items in Figure Classification and Figure Analogies had no DIF effect, some items in Figure Synthesis and matrices had DIF effect. Based on the results, recommendations were ma de that DIF should be used by test developers to eliminate bias amongst others.