Validity of the Strong Interest Inventory® Instrument

The Strong Interest Inventory® (Strong) assessment measures career and leisure interests. It is based on the work of E. K. Strong Jr., who originally published his inventory on the measurement of interests in 1927. The assessment is often used to aid people in making educational and career decisions.

The Strong assessment measures interests in four main categories of scales: General Occupational Themes (GOTs), Basic Interest Scales (BISs), Personal Style Scales (PSSs), and Occupational Scales (OSs): 

The current norm sample for the Strong is called the General Representative Sample (GRS) and consists of 2,250 individuals (50% men, 50% women). The GRS is generally representative of the racial and ethnic makeup of the U.S. workforce (Donnay, Morris, Schaubhut, & Thompson, 2005). All scales are measured using the GRS, except the OSs (as described above).

Internal consistency reliabilities of all scales are high. GOT reliabilities range from .90 to .95, BISs from .80 to .92, and PSSs from .82 to .87. Determining internal consistency reliability is not appropriate for the OSs because the scales contain items with heterogeneous content and are empirically derived.

Extensive research has demonstrated the validity of the Strong Interest Inventory instrument:

References

Borgen, F. H., & Lindley, L. D. (2003). Optimal functioning in interests, self-efficacy, and personality. In W. B. Walsh (Ed.), Counseling psychology and optimal human functioning (pp. 55-91). Hillsdale, NJ: Lawrence Erlbaum Press. 

Campbell, D. P. (1966). Occupations 10 years later of high school seniors with high scores on the SVIB life insurance salesman scale. Journal of Applied Psychology, 50, 369-372. 

Dirk, B. J., & Hansen, J. C. (2004, February). Development and validation of discriminant functions for the Strong Interest Inventory®. Journal of Vocational Behavior, 64 (1), 182-197. 

Donnay, D. A. C., & Borgen, F. H. (1996). Validity, structure, and content of the 1994 Strong Interest Inventory®. Journal of Counseling Psychology, 43, 275-291. 

Hammer, A. L., & Kummerow, J. K. (1996). Strong and MBTI® career development guide (rev. ed.). Mountain View, CA: CPP, Inc. 

Hansen, J. C., & Swanson, J. L. (1983). Stability of interests and the predictive and concurrent validity of the 1981 Strong-Campbell Interest Inventory for college majors. Journal of Counseling Psychology, 30, 194-201. 

Harmon, L. W. (1969). The predictive power over 10 years of measured social service and scientific interests among college women. Journal of Applied Psychology, 53, 193-198. 

Holland, J. L. (1959). A theory of vocational choice. Journal of Counseling Psychology, 6, 35-45. 

Isaacs, J. Borgen, F. H., Donnay, D. A. C, & Hansen, T. A. (1997). Self-efficacy and interests: Relationships of Holland themes to college major. Poster presented at the annual meeting of the American Psychological Association, Chicago, IL. 

Larson, L. M. & Borgen, F. H. (2002). Convergence of vocational interests and personality: Examples in an adolescent gifted sample. Journal of Vocational Behavior, 60, 91-112. 

Rottinghaus, P. J., Lindley, L. D., Green, M. A., & Borgen, F. H. (2002). Educational aspirations: The contribution of personality, self-efficacy, and interests. Journal of Vocational Behavior, 61, 1-19. 

Strong, E. K., Jr. (1935). Predictive value of the Vocational Interest Test. Journal of Educational Psychology, 26, 332. 

Strong, E. K., Jr. (1955). Vocational interests 18 years after college. Minneapolis: University of Minnesota Press. 

Tuel, B. D., & Betz, N. E. (1998). Relationships of career self-efficacy expectations to the Myers-Briggs Type Indicator® and the Personal Style Scales. Measurement and Evaluation in Counseling and Development, 31, 150-163.