Trait and factor, the Minnesota point of view, differentialist, directive, and
decisional all describe a counseling approach centered in four decades of
writings by Edmund Griffin Williamson and his colleagues at the University of
Minnesota. The classic trait-factor approach that Donald Paterson, John Darley,
and E. G. Williamson proposed in the late 1930s was a direct outcome of their
investigation of a variety of settings. Going back to the late nineteenth and
early twentieth centuries, they integrated Galton's empirical and systematic
attempts to measure differences in individual capacities and aptitudes;
investigations by Binet in France and Cattell in America of differential
prediction of intelligence; and Munstenberg's utilization of such individual
differences in industrial applications. They then bound these psychometric
approaches to Frank Parson’s theories of vocational guidance