Theoretical Infrastructure
The approach of Holland's (1997) personality types has been selected to create the infrastructure of the system. Holland's theory of personality types is one of the most widely used theories in vocational assessment (Gottfredson, 1999) and is the most comprehensive and influential theory of occupational interest (Tracey and Gupta, 2008). The Strong Interest Inventory, Self-Directed Search Scale (SDS) and UNIACT are some of the most commonly used scales in career counseling based on the same approach as Holland's personality types (Armstrong, Allison, and Rounds, 2008). One of the advantages of the theory over many other theories is that it is a practical theory that has been developed since the beginning of its development and has been revised several times based on feedback from applications (Gottfredson, 1999). Other factors that make Holland's theory of personality types so widely accepted include its widespread use in directing careers by many organizations and institutions (Laurence, 2004), its examination and revision through over 100 studies conducted by researchers in 1959, 1966, 1973, 1985, and 1997 (Gottfredson, 1999), and its status as the most researched occupational choice theory abroad (Harrington and Feller, 2004).
The theory of Holland (Holland, 1997) consists of a few simple ideas and more complex components. First, people can be classified based on how much they resemble one of six personality types (Realistic, Investigative, Creative, Social, Entrepreneurial, Conventional). People who show a high degree of similarity to one type are likely to exhibit personality traits and behaviors associated with that type. Second, people's living and working environments can be described based on one of six environmental models (Realistic, Investigative, Creative, Social, Entrepreneurial, Conventional) that resemble it. Finally, by matching individuals and environments, procedures can be made based on information related to personality types and environmental models. These procedures may include career choice, occupational commitment and success, educational choice and success, self-efficacy, social behavior and sensitivity to influence.