Factorial verbal and performance IQs derived from the WISC-R: their psychometric properties

A method is discussed for securing Factorial Verbal and Factorial Performance IQs from the WISC-R by means of an orthogonal rotation of the axes that describe the plane of the first two principal components derived from an analysis of the intercorrelations of the WISC-R subtests. The reliability and validity of these IQs also are described. Sex differences in normal children are found, as well as differences between normal and learning-disabled children.