Indices of motivation and demand developed to forecast postsecondary enrollment in Manitoba, Canada, are described. The indices were tested with surveys of more than 14,000 high school students with respect to actual outcomes and validated by surveying more than 5,000 students. The theoretical basis of the indices, their use in enrollment forecasting, and the accuracy of the enrollment demand prediction model are discussed. It is concluded that the use of the motivational index is to provide an aggregate measure of the motivation of students toward postsecondary education. An aggregate measure of postsecondary demand may also be developed for the demand index. This measure is composed of both student motivation and its background influencing variables such as parents' income and father's education. This index can be used to give a measure of the total demand for postsecondary education and the probability of attending postsecondary education. (SW)