Journal of Vocational Behavior 29, 254-291 (1986) MONOGRAPH Occupational Aptitude Patterns Map: Development and Implications for a Theory of Job Aptitude Requirements LINDA S. GOTTFREDSON Counseling and Personnel Services, University of Maryland, College Park; and Center for Social Organization of Schools, The Johns Hopkins University United States Employment Service data on the cognitive and noncognitive aptitude requirements of different occupations were used to create an occupational classification-the Occupational Aptitude Patterns (OAP) Map. The OAP Map consists of 13 job clusters arrayed according to major differences in overall intellectual difficulty level and in functional focus (field) of work activities. The OAP Map was compared with an alternative, aptitude-based classification, with the Holland typology of work environments, and with ratings for complexity of involvement with data, people, and things. Those comparisons provided con- siderable evidence concerning the construct validity of different aspects of the Map and helped to clarify the uses for which the Map is most appropriate. When combined with previous evidence about patterns of job aptitude demands, the OAP Map provides the basis for a theory of job aptitude requirements. The OAP Map and accompanying analyses support the following hypotheses: (1) general intelligence is the major gradient by which aptitude demands have become organized across jobs in the U.S. economy, (2) within broad levels of work, the aptitude demands of different fields of work differ primarily in the shape of their cognitive profiles, and (3) different aptitude demand patterns arise in large part from broad differences in the tasks workers actually perform on the job. Q 1986 Academic PKSS, Inc. Job description and classification have been of considerable concern in the effort to design more effective, efficient, and fair counseling and employment practices (Holland, 1985; Pearlman, 1980). In particular, the U.S. Employment Service (USES) has produced a wealth of information The research reported here was supported partly by Grant NIE-80-0013 from the National Institute of Education. The opinions expressed in this paper do not necessarily reflect, the position or policy of NIE, and no official endorsement by the Institute should be inferred. I thank John Burke and Valerie Sunderland for their assistance in coding and tabulating data. Correspondence, including requests for reprints, should be addressed to Linda S. Gottfredson, Center for Social Organization of Schools, The Johns Hopkins University, Baltimore, MD 21218. 254 OOOl-8791/86 $3.00 Copyright 0 1986 by Academic Press, Inc. All rights of reproduction in any form reserved.