Strong Interest Inventory (SII)

Intended for high school and college students and adults, the Strong Interest Inventory (SII) serves as an interest register.  Participants use this instrument to investigate their interests and preferences in a collection of areas: Occupations, leisure activities, types of people, and school samples.

Subjects will have to respond to 317-items using a 3-point scale, which are then compared with other responses from people in different occupation and types. Approximately 30 to 40 minutes is required for completion.

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Edward K. Strong Jr., David P. Campbell, Lenore W. Harmon, Jo Ida C. Hansen, Fred H. Borgen, & Allen L. Hammer, 1994.

Reliability and Validity

Data provided in the technical guide supports strong reliability and validity.  Over short-term time periods, the test-retest reliabilities for four samples ranged from 0.74 to 0.92. Alpha reliability for the General Occupational Themes were reported at 0.90 to 0.94, 0.74 to 0.94 for Basic Interest Scales, and none was reported for Occupational Scales.  A correlation score of 0.77 was calculated between the General Occupational Themes and the Vocational Preference Inventory Scales.  According to Holland’s hexagonal model which the SII is based, construct validity is supported in the theme intercorrlations.

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Administration, Analysis and Reporting

Statistics Solutions consists of a team of professional methodologists and statisticians that can assist the student or professional researcher in administering the survey instrument, collecting the data, conducting the analyses and explaining the results.

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Anderson, M. Z., Tracey, T., & Rounds, J. (1997). Examining the invariance of Holland’s vocational interest model across gender. Journal of Vocational Behavior, 50, 349-364.

Fouad, A., Harmon, L. W., & Borgen, F. H. (1997). Structure of interests in employed male and female members of U. S. racial-ethnic minority and nonminority groups. Journal of Counseling Psychology, 44, 339-345.

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

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.

Review of the Strong Interest Inventory by Kevin R. Kelly. Purdue University, West Lafayette, IN.

Review of the Strong Interest Inventory by Eugene P. Sheehan. University of Northern Colorado, Greenly, CO.

Rounds, J. (1995). Vocational interests: Evaluating structural hypotheses. In D. J. Lubinski & R. V. Dawis (Eds.), Assessing individual differences in human behavior: New concepts, methods, and findings (pp. 177-232). Palo Alto, CA: Davies-Black.

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. View