“…In a majority of these analyses, the two factors correspond closely to Wechsler's a priori division of the scale into Verbal and Performance sections (Silverstein, 1969(Silverstein, , 1977(Silverstein, , 1980. This factor, however, has proven to be less robust and less invariant across different clinical samples (Berger et al , 1964;Groff & Hubble, 1982;Kaufman, 1979;Reed & Fitzhugh, 1967;Rugel, 1974;Silverstein, 1970). In addition to the Verbal and Performance factors, a number of studies have extracted a third factor (Baumeister & Bartlett, 1962a, 1962bBerger, Bernstein, Klein, Cohen, & Lucas, 1964;Cohen, 1952Cohen, , 1957Cohen, , 1959Russell, 1972;Van Hagen & Kaufman, 1975).…”