Assessing factor structure and measurement invariance of WISC-IV among almajiris attending quranic schools and pupils attending mainstream public primary schools in Northern Nigeria

We examined the factor structure and measurement invariance of the Weschler Intelligence Scale for Children (WISC-IV)- among 11-16-year-old <i>Almajiris</i> (street boys attending Quranic school) in Northern Nigeria, and age-comparable mainstream public primary school boys. Across 200 <i>Almajiris</i> and 201 public school children, we tested multiple plausible models to confirm the factor structure of WISC-IV, with the four-factor model (reflecting the four WISC domains) showing best fit for both groups. We then tested the four-factor model's measurement invariance using multi-group confirmatory factor analysis, which revealed full metric invariance between the two groups and partial scalar invariance, with subtests of the Working Memory Index (WMI) showing insufficient equivalence (internal bias). Further, examination of the latent means revealed that on the remaining domains VCI, PRI and PSI <i>Almajiris</i> as a group showed poorer performance than public school children (PSCs) not attributable to the bias of the subtests (external bias). Our study highlights within-country sub-population differences in the functioning of western tools in cross-cultural contexts, while offering cautious support for measurement invariance in certain domains of the WISC-IV (VCI, PRI and PSI) in this non-Western population.