The fit of Holland's RIASEC model to US occupations

Holland's [Holland, J. L. (1959). A theory of occupational choice. Journal of Counseling Psychology, 6, 35-45; Holland, J. L. (1997). Making vocational choices: A theory of vocational personalities and work environments (3rd ed.). Odessa, FL: Psychological Assessment Resources, Inc.] RIASEC types were initially developed using a restricted range of occupational titles. Holland's type classification system has been extended to encompass the full range of occupations in the US, using both statistical and expert rating methods. However, the extent that Holland's classification model is sufficient to represent the full range of occupational interests has not been examined. Multidimensional scaling (MDS) was used to analyze college students' (266 men, 572 women) interests in occupations representing approximately 85% of the US labor market. A two-dimensional MDS solution of the full set of occupations did not fit Holland's model, but limiting the analysis to occupations used in Holland-based measures produced the expected RIASEC structure. In comparison, a three-dimensional solution included Prediger's [Prediger, D. J. (1982). Dimensions underlying Holland's hexagon: Missing link between interests and occupations? Journal of Vocational Behavior, 21, 259-287] dimensions (Things/People and Data/Ideas) consistent with Holland's model, but also included prestige and sex-type dimensions that were not orthogonal to Prediger's dimensions. These results demonstrate that the RIASEC types are not sufficient to represent the full range of occupational interests and are confounded with prestige and sex-type.