10th U6+ Consortium of African Universities International Conference

Persistent underperformance in NECO SSCE Mathematics has raised concerns about the fairness of test items for different student groups in Nigeria. This study investigates Differential Item Functioning (DIF) in the 2024 NECO Mathematics multiple-choice questions to determine whether items favored certain groups. The study had three main objectives: (i) to examine gender-based DIF, (ii) to examine DIF based on school type (public vs. private), and (iii) to determine DIF by school location (urban vs. rural). A descriptive survey design was used. The sample included 294 Senior Secondary School students in Ilorin, Kwara State, selected using stratified sampling to fairly represent different genders, school types, and locations. The instrument was a set of 60 standardized NECO Mathematics multiple-choice items. Logistic regression was used to detect DIF. Findings revealed that: on Gender: 56 items were fair, but 4 favored male students; with respect to school type, 19 items favored private school students while on location, 5 items favored urban students. In total, 28 items showed moderate to large DIF, suggesting possible bias that could affect test validity and fairness. The study recommends revising biased items, aligning test content with diverse learning environments, and using contexts familiar to all students—regardless of gender, school type, or location.