McCrae RR, Costa PT, Jr. Rotation to maximize the construct validity of factors in the NEO Personality Inventory. Multivariate Behavioral Research 1989;24(1):107-124.

The NEO Personality Inventory (NEO-PI) consists of 5 global domain and 18 specific facet scales developed to measure neuroticism, extraversion, openness to experience, agreeableness, and conscientiousness in normal personality. To obtain optimal measures of these 5 dimensions, a method for the orthogonal rotation of principal components to maximize the convergent and discriminant validity of the rotated factors (validimax rotation) is proposed. Data from 983 men and women (aged 19-93 yrs) were used to obtain the factors. The rotation was cross-validated on peer and spouse ratings on the NEO-PI and in a 2nd sample of 100 men. NEO-PI domain scales, varimax factors, and validimax factors all suggest construct validity, but validimax factors were superior, especially as measures of Agreeableness and Conscientiousness.