Monthly Archives: August 2013

Test-retest effects : No g gains in two independent samples

I analyze two studies who provide the necessary data for studying the test-retest effects, namely, Watkins (2007), Schellenberg (2004, 2006). Both used the Wechsler’s subtests, and the correlations between the IQ changes among those subtests with g-loadings are negative, in … Continue reading

Posted in Psychometrics | Tagged

Genetic and environmental contributions to population group differences on the Raven’s Progressive Matrices estimated from twins reared together and apart

Genetic and environmental contributions to population group differences on the Raven’s Progressive Matrices estimated from twins reared together and apart J. Philippe Rushton, Trudy Ann Bons, Philip A. Vernon and Jelena Čvorović (2007) We carried out two studies to test … Continue reading

Posted in Behavioral Genetics, Psychometrics | Tagged