How Reliably Can We Measure a Child's True IQ? Socio-Economic Status Can Explain Most of the Inter-Ethnic Differences in General Non-verbal Abilities

Roma children have been discriminated against for many years as they are denied access to high-quality education based on their scores on general non-verbal IQ tests.Rushton et al. (2007)showed that Roma perform more poorly than non-Roma on one such test (i.e., Raven Progressive Matrices), but suggest that this underperformance could be explained by Roma's low socio-economic status. In this paper, we tested the non-verbal abilities of Roma children and expanded on the research ofRushton et al. (2007)by investigating empirically the potential mediating effects of socio-economic status on children's performance on Raven Progressive Matrices. Results showed that the performance of Roma children was, on average, significantly lower than the performance of their non-Roma peers; however, the effect of ethnicity was partially mediated by the parents' education and living conditions (while the parents' income had no significant effect). As hypothesized byRushton et al. (2007)some socio-economic factors can explain important variability in the performance of Roma children on general non-verbal tests, and their poor performance on such tests may lead to an underestimation of the true population mean.