The Epistemology of Assessment: Validity, Fairness, and the West African Senior School Certificate Examination in Nigeria

This study provides a comprehensive epistemological analysis of the West African Senior School Certificate Examination as Nigeria's high-stakes secondary education assessment instrument, examining its validity, fairness, and fitness for its claimed educational and social selection purposes. High-stakes examinations function as epistemological gatekeepers, shaping what knowledge counts, whose knowledge is valued, and which students gain access to higher education and social mobility. The WASSCE, administered by the West African Examinations Council, plays this gatekeeper role for millions of Nigerian students annually, yet its epistemological foundations and equity implications have not been systematically interrogated. This study employs a critical philosophical and psychometric mixed-method design. Philosophical analysis draws on validity theory from Messick and Mislevy alongside epistemic justice frameworks. Psychometric analysis uses item response theory modelling applied to five years of released WASSCE item data from Mathematics, English, and Economics papers. Differential item functioning analysis assesses fairness across gender, geopolitical zone, and school type subgroups. Qualitative data from 30 interviews with WAEC officials, curriculum specialists, and education equity researchers supplement the quantitative work. Results reveal significant differential item functioning patterns disadvantaging rural and northern school students in English and Economics. Construct validity is compromised by curriculum-examination misalignment in several subjects. Philosophical analysis identifies hidden epistemological assumptions that privilege urban, English-dominant knowledge frameworks. The study concludes that the WASSCE has significant validity and fairness limitations that undermine its educational and social selection purposes. It recommends a comprehensive examination reform process guided by validity and epistemic fairness principles.

Keywords: assessment epistemology, WASSCE, validity, fairness, high-stakes examination Nigeria.