Costa PT, Jr., McCrae RR. Ego development and trait models of personality. Psychological Inquiry 1993;4(1):20-23.

Comments that J. Loevinger is wrong in assuming that only ego level (or the related dimensions of openness and intelligence from the 5-factor model of personality) influences the expression of other traits. Possibly all major personality factors can be seen as master traits, because all of them condition the expression of other traits.