The Wisconsin model of socio-economic attainment is a model that describes and explains an individual's social mobility and its economic, social, and psychological determinants. The logistics of this model are primarily attributed to William H. Sewell and colleagues including Archibald Haller, Alejandro Portes and Robert M. Hauser. The model receives its name from the state in which a significant amount of the research and analysis was completed. Unlike the previous research on this topic by Peter Blau and Otis Dudley Duncan, this model encompasses more than just educational and occupational factors and their effect on social mobility for American males. The Wisconsin model has been described as "pervasive in its influence on the style and content of research in several subfields of sociology." Prior research Before the framework for the Wisconsin model was constructed, Peter Blau and Otis Duncan established the first model of social mobility of its kind. However, the Blau-Duncan model was made up of only five predictors. These included father's education and occupation, the individual's education and first job, and the individual's job several years later. Purpose Sewell and his counterparts aimed to contribute to the Blau-Duncan model of status attainment by adding predictor variables. Because the results given by the Blau-Duncan model were based heavily on "structural factors as explanatory variables", the Wisconsin model was created to account for "social-psychological factors on educational and occupational attainment", which in turn, provided more accurate prediction. These variables, in turn, came from analyses done by Sewell and Haller in the 1950s and published (with Sewell's agreement) by Haller and Miller (1963, 1971). The latter work includes the theory on which the psychosociological variables of the WM are based. Model variables The model consisted of eight characteristics that most effectively linked socio-economic background and status attainment. These included occupational attainment, educational attainment, level of occupational aspiration, level of educational aspiration, the influence of significant others, academic performance, socioeconomic status, and mental ability. Occupational attainment Measured by Otis Dudley Duncan's socio-economic index of occupational status. Educational attainment Achieved by assigning a point value to certain levels of education that a subject has reached. In more recent studies using this model, educational attainment was classified into four levels: no post high school education, vocational school, college attendance, and a college degree. Earlier studies only classified subjects into those who went to college and those who did not. Level of occupational aspiration The