Assessment of the Unidimensionality and Differential Item Functioning in the 2017 West African Examination Council (WAEC) November/December Mathematics Multiple Choice Test Items

Abstract

This study assessed unidimensionality and occurrence of Differential Item Functioning (DIF) in the 2017 November/ December West African Examination Council (WAEC) Mathematics test items administered in Edo State. The population for the study consisted of all the responses of students who answered the 2017 WAEC November/ December Mathematics multiple choice Examination. A sample of 1,238 Senior School III students’ responses to 50 multiple-choice WAEC 2017 Mathematics multiple choice items selected using stratified and random sampling techniques was used in the study. Research instrument used for the study were adopted 50 multiple-choice 2017 WAEC November/ December Mathematics multiple choice test items. Cronbach Alpha technique was used to determine the reliability of the instrument and the reliability coefficient of 0.87 was gotten. Data collected were analysed using Raju Area Measure technique, Chi-square and Principal Component Analysis. The results showed that the 2017 WAEC November/ December Mathematics multiple choice test items is unidimensional. Also, there was occurrence of DIF items in the 2017 WAEC November/ December Mathematics multiple choice test items. Twelve items representing 24% of the 50 items in the Mathematics examination exhibited DIF. Based on the findings, it was recommended among other things that examination bodies should take a deliberate decision to intensify reviewing of items including multiple choice items to determine the extent to which each item meets the assumptions of the IRT model under consideration.