An Assessment of Item Statistics Estimates of Basic Education Certificate Examination through Classical Test Theory and Item Response Theory approach

Abstract

In this study, the researchers assessed comparability of item statistics of 2017 basic education certificate mathematics examination of National Examinations Council (NECO) through Classical Test Theory (CTT) and Item Response Theory (IRT) measurement frameworks. The study adopted instrumentation design. A 60-item NECO basic education certificate education mathematics objective test paper I was administered to 978 basic nine examinees, randomly selected from Osogbo and Olorunda Local Government Area, Osun State, Nigeria. The responses of the examinees to the test data were analysed using Marginal Maximum Likelihood Estimation of JMETRIK software.  The result showed that the test data obey the assumption of unidimensionality of 3-parameter logistic model and Classical Test Theory measurement framework deleted more items 33 (55%) compare to IRT measurement framework 12 (20%). Also, it was observed that item statistics from the two contrasting frameworks (CTT and IRT) were not comparable. Moreover, further analysis showed that there was low correlation among the item statistics index. The implication of this is that NECO should jettison the use of Classical Test Theory and embrace utilization of Item Response Theory framework during their test development and item analysis.