Aminu, Danladi AbubakarAnyanwu, L/NAnikweze, N/A2023-12-132023-12-132020-01-20Awopeju, O.A. & Afolabi, E.R. I. (2016).Comparative Analysis of Classical Test Theory and Item Response Theory Based Item Parameter Estimates of Senior School Certificate Mathematics Examination. European Scientific Journal, 12 (28):263- 284 Gulcr, N., Uyanik, G. K., &Teker, G.T. (2014). Comparison of Classical Test Theory and Item Response Theory in terms of Item Parameters. In European Journal of Research on Education (EJRE). Published by International Association of Social Science Research - IASSR ISSN: 2147-6284, 2(1), 1-6; Available Online at http://iassr.org/joumal 2013 (c) Kukwi, I. J. & Amos, I. (201 ^.Essentials of educational measurement and evaluation.KadunaL, Image point publishers. Lin, C. J. (2008). Comparisons between Classical Test Theory and Item Response Theory in Automated Assembly of Parallel Test Forms. Journal of Technology, Learning, and Assessment, 6(8). Retrieved [date] from http://www.jtla.org. Mead, A. D. & Adam, W. M. (2014). Test Construction using CTT and IRT with Unrepresentative Samples Alan D. Mead, College of Psychology, Illinois Institute of Technology, 3101 South Dearborn, Chicago, IL 60616. E-mail: mead@iit.edu Nasir, M. (2014). Application of Classical Test Theory and Item Response Theory to Analyze Multiple Choice Questions. A Thesis Submitted to the Faculty of Graduate Studies in Partial fulfillment of the requirements for the Degree of Doctor of Philosophy Department of Medical Science Calgary, Alberta.https://keffi.nsuk.edu.ng/handle/20.500.14448/4319The thrust of this study was to compare Classical Test Theory (CTT) and Item Response Theory (IRT) ability estimates of secondary school Economics students’ in Federal Capital Territory, Abuja. Descriptive survey research design was employed. The population of the study consisted of 18,643 SS II students from 206 Senior Secondary Schools that offered Economics at Senior School Certificate Examinations. The sample of the study comprised 903 SS II Economics students from 23 Senior Secondary Schools in the Federal Capital Territory, Abuja. A50-item Economics Achievement Test (EAT). The split half reliability coefficient of EAT was 0.93. The research questions were answered using descriptive statistics while the hypotheses were tested using t-test statistic. The findings showed that the items have moderate psychometric indices when tested using CTT model while the psychometric properties as depicted by IRT indicated that one item was outside the acceptable range. Also, there was significant difference in the difficulty indices of Economics test items between CTT and IRT among the tastes. On the whole, the study established that IRT model possess better ability estimation than CTT. It was thus, recommended that Examination Bodies should use IRT model for more accurate estimation of candidates’ ability.enAbility Estimates, classical test theory, Item Response TheoryArticle