Abstract
Publication of the Stanford-Binet Intelligence Scale, Fourth Edition has resulted in publication of at least six factor analyses of the instrument. After the principles for factor analysis are discussed, four of these analyses are reviewed and criticized in detail, and two others are noted. After the shortcomings of previous analyses are described, factor analyses of the standardization data are reported that are based on principal axis factorings of the age-specific and age-grouped correlation matrices with Oblimin rotation. At ages 2 through 7 the instrument produced two correlated factors of verbal and nonverbal ability. Above age 7 there are three correlated factors: verbal ability, abstract/spatial ability, and memory. The correlations among the primary factors are taken as evidence of a second-order factor of general intelligence. The factors remain stable across age levels. Analysis of the median correlations across all ages yielded evidence of the four factors hypothesized by the test constructors.