Holland Codes

The Holland Codes or the Holland Occupational Themes (RIASEC), developed by the late psychologist John L. Holland, refers to a theory of careers and vocational choice based upon personality types. Each letter or code stands for a particular "type": Realistic (Doers), Investigative (Thinkers), Artistic (Creators), Social (Helpers), Enterprising (Persuaders), and Conventional (Organizers)."

According to the Committee on Scientific Awards, Holland's "research shows that personalities seek out and flourish in career environments they fit and that jobs and career environments are classifiable by the personalities that flourish in them." Holland also wrote of his theory that "the choice of a vocation is an expression of personality." Furthermore, while Holland suggests that people can be "categorized as one of six types, " he also argues that "a six-category scheme built on the assumption that there are only six kinds of people in the world is unacceptable on the strength of common sense alone. But a six category scheme that allows a simple ordering of a person's resemblance to each of the six models provides the possibility of 720 different personality patterns."

The US Department of Labor/Employment and Training Administration (USDOL/ETA) has been using the RIASEC model in the "Interests" section of its free online database, The Occupational Information Network (O*NET) since its inception during the late 1990s.