Wicherts (Reference Wicherts2018) argues that when testing Spearman’s hypothesis item-level data should be analysed using item response theory and not with the method of correlated vectors (MCV). Astonishingly, in a paper on the heritability and culture-loadedness of subtests of IQ batteries (Kan et al., Reference Kan, Wicherts, Dolan and Van der Maas2013) he used the very same technique.

Wicherts ignores the psychometric meta-analytic–MCV hybrid model (te Nijenhuis et al., Reference te Nijenhuis, van Vianen and van der Flier2007, Reference te Nijenhuis, Bakhiet, van den Hoek, Repko, Allik, Žebec and Abduljabbar2016) with its corrections for sampling error, reliability of the g vector, reliability of the second vector, restriction of range in g loadings and imperfectly measuring the construct of g. Wicherts focuses only on the individual correlations between two vectors of item scores, so Wicherts is attacking a strawman. Wicherts’ criticism at the item level is eerily similar to Schönemann’s (Reference Schönemann1997) criticism at the subtest level that MCV will automatically lead to positive correlations. Schönemann’s position has been thoroughly undermined by the large amount of negative correlations from subtest-level studies. A strong negative correlation (r=−0.39) was found in a study on learning potential at the item level (te Nijenhuis et al., Reference te Nijenhuis, van Vianen and van der Flier2007), which after corrections for artifacts might easily become r=−0.60.

Wicherts argues that relations studied with MCV are quite complex. However, from the perspective of the psychometric meta-analytic–MCV hybrid model this is to be expected, as the influences of no less than five statistical artifacts on the observed correlation have to be taken into account at the same time.

Wicherts (Reference Wicherts2018) brings up the point that, recently, reviewer Wicherts suggested to the present authors to cite an unpublished paper from himself; however, this constitutes misuse of the reviewer position. Obviously, a paper should first be accepted by the reviewers, by a selection from the forum of peers (de Groot, Reference de Groot1969).