subject's level is calculated by again categorizing Duncan's socioeconomic index scores in association with the occupation that the subject hope to hold in the future. Level of educational aspiration This is classified by the education level that each subject originally indicates that they hope to secure. Once again, some recent studies have assigned point values for three levels of desired education level: not continuing education after high school, vocational school, or college. Previous studies only categorized students based on which type institution they planned on attending prior to high school graduation. Significant others' influence This variable can be determined by evaluating three perceptions of the subject including: parental and teacher encouragement to attend college, as well as friends' college plans. Additional work regarding the influence of significant others on occupational aspirations was subsequently done by Haller and is students Joseph Woelfel and Ed L. Fink. The original Sewell, Haller and Portes article Sewell which first reported the broad outlines of the Wisconsin model relied on data from a statewide survey of all Wisconsin high school seniors that included information about whether students perceived their parents, teachers and friends as expecting them to go to college. Later work initiated by Archie O. Haller and implemented by Joseph Woelfel and Edward L. Fink was able to survey adolescent students and identify the specific persons who communicated most with them about education and occupation, and who served as examples for their own educational and occupational futures. The "Significant Other Project" also produced survey instruments which identified the specific significant others for educational and occupational aspirations and measured their educational and occupational aspirations for the students Academic performance This value is calculated by the subject's high school class rank. Socioeconomic status In the original study, socio-economic status was determined by a weighted combination of mother's and father's education, father's occupation, and average annual income from 1957-1960. Mental ability This variable is determined by the analysis of standardized testing. In previous studies, statewide test results for high school juniors and seniors are compared with state intelligence norms. Effects of social psychology and stratification research on the process of status attainment Interpersonal influence Primarily, the significant others' direct influence on the subject specifically relates to one's educational and occupational aspirations and also educational attainment. Basically, this implies that those who are constantly involved with a subject (mother, father, friend) will have a direct outcome on what