APPLICATION OF ITEM RESPONSE THEORY IN THE VALIDATION OF BASIC SCIENCE TEST OF DELTA STATE BASIC EDUCATION CERTIFICATE EXAMINATION

Abstract

The purpose of this study is to apply item response theory of measurement to validate the Basic Science Test of the Delta State Basic Education Certificate Examination. Four research questions guided the study. The study adopted the multiple triangulation research design. The population of the study comprised all public Upper basic school students in Delta State, Nigeria. The sample size comprised 1,000 JSS 3 students in public secondary schools in Delta State. The sampling technique that was used for the study is proportionate stratified, simple random and convenience sampling techniques. The main instrument that was used for the study is the Basic Science Test (BST) that is under validation. Another instrument that was used is the Physical and Health Education Test (PHET) that was used to establish the concurrent validity of the Basic Science Test. The a, b and c parameters item response theory dichotomous models were used to answer research questions 1, 2 and 3 respectively. Pearson product moment correlation coefficient was used to answer research question 4. The findings of the study revealed that majority of the items in the test are moderately difficulty and partially fall in line with the ability level of the students for whom the test was made; that majority of the items in the test discriminated well between higher achievers and low achievers; that majority of the items are not guessable; and that the BST has a very high concurrent validity. Based on the findings, it can be concluded that IRT and CTT can play a complementary role in test development. The study recommended that the validate Basic Science Test should be added to the already existing item pool.