IntraindlviduaI differences in verbal and numerical abilities have been observed since the inception of appropriate measuring Instruments. Whether verbal and numerical ability occur in the form of a continuous distribution or as dichotomous categories has both theoretical and practical importance. That such variation has meaning in terms of predictable college academic success is recognized. Less apparent, but equally important, are relationships between Intraindividual verbal and numerical variation and personality characteristics and/or psychopathology. In college situations the American Council on Education Psychological Examinatipn (ACE), with Linguistic (l) and Quantitative (Q) components, and the School and College Ability Tests (SCAT), with Verbal (V) and Quantitative (Q) components, are traditionally used to predict academic achievement.
Dana, Richard H. and Dahlke, Arnold E., "Intraindividual Verbal-Numerical Discrepancies: Dichotomy or Continuum, Personality Characteristic or Psychopathology?" (1962). Regional Research Institute. 37.