He served in the army for more than three years, working as a test proctor and psychological assistant, among other duties. His interest in the classification of individuals into set psychological types began here, as he watched army recruits sorted according to results obtained from a short interview form. At the University of Minnesota, he obtained a doctorate in counseling psychology.
Holland’s subsequent career counseling experience showed him the drawbacks of existing career tests. Long scoring times, inadequate client information, and the absence of an organized occupations list that coordinated with test results made administrations frustrating. So in 1953 Holland created the Vocational Preference Inventory (VPI). VPI results were comparable with those obtained from existing tests despite its lack of norms and unequal scale lengths. The VPI’s significance lay in its inclusion of occupational lists and its organization of items into scales—the predecessor to the hexagonal model.
Over the next 27 years, Holland worked in a VA psychiatric hospital, the National Merit Scholarship Corporation, the American College Testing Program, and Johns Hopkins University, all the while honing his theory according to the latest research. In 1970, he published the Self-Directed Search, which has enjoyed four revisions since. The accompanying occupational classification system, known as the Occupations Finder, was first published in 1977 and has also been refined throughout the years. The Position Classification Inventory, developed in 1991, allowed Holland’s theory to be applied to existing positions and organizations.
Holland retired in 1980 but didn’t stop working on his theory. In fact, he revised it again in 1997, incorporating an environmental identity aspect, among making other changes. In 1995, Holland received the prestigious American Psychological Association Award for Distinguished Contributions to Knowledge for his theory of careers that “provided an intellectual tool for integrating our knowledge of vocational intentions, vocational interests, personalities, and work histories.” He died in 2008