SummaryWicherts (2018) criticizes the use of the method of correlated vectors when testing Spearman's hypothesis. It is argued that Wicherts ignores the psychometric meta-analytic method of correlated vectors hybrid model and so is attacking a strawman.
SummarySpearman's hypothesis tested at the level of items states that differences between ethnic groups on the items of an IQ test are a function of thegloadings of these items, such that there are small differences between ethnic groups on items with lowgloadings and large differences between ethnic groups on items with highgloadings; this has been confirmed in a limited number of studies. In this paper, Spearman's hypothesis was tested, comparing a group of Saudi children and adolescents (N=3209) with other groups of children and adolescents from Denmark, Cyprus, Croatia, Bosnia, South Africa, Estonia, Ukraine, Ireland, Russia and Chile (totalN=9333). The analyses were carried out on twelve comparisons between the Saudi Arabian children and the other children. Spearman's hypothesis was confirmed less strongly than in other large-scale studies with a mean weightedrvalue of 0.44. The relevance of these findings for the discussion on the causes of group differences is discussed.
