CPP Research Center

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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 current General Representative Sample (GRS) for the Strong consists of 2,250 individuals (50% men, 50% women) and is representative of the gender, racial, and ethnical makeup of the U.S. workforce (Donnay, Morris, Schaubhut, & Thompson, 2005). All scales are measured using the GRS, except the Occupational Scales (OS).

Internal consistency reliabilities of all scales are high. General Occupational Theme (GOT) reliabilities range from .90 to .95, Business Interest Scales (BISs) from .80 to .92, and Personal Style Scales (PSSs) from .82 to .87. Internal consistency reliability is not appropriate for the OSs because the scales contain items with heterogeneous content and are empirically derived.

The Strong Interest Inventory® Manual is the most comprehensive guide to administering the Strong assessment and features information on the tool’s reliability and validity, detailed descriptions of the scales, and O*Net™ codes. This page contains the research to further support the reliability and validity of the Strong tool, as well as best practices and industry trends when applying the assessment results in different settings. You will also find information on ways to pair the instrument with other assessments for maximum effectiveness.

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