The first panel of a three-year longitudinal study was conducted to investigate the process by which youth form career expectations. The study was designed around a cross-sectional path model of career expectations drawn from the sociological literature on status attainment and is based on differential equations in which all expectation variables are viewed as affecting each other in a time-continuous system of feedback loops. A random sample of approximately 700 Ohio high school sophomores completed self-administered questionnaires providing data on career expectations and socioeconomic characteristics of family members. One or both parents of each youth also completed questionnaires identifying the parents' career expectations for their children and socioeconomic data. All occupational data were coded into three-digit 1970 census codes and then transformed into codes reflecting socioeconomic content of occupations. Selected means, standard deviations, correlations, and path models were compared to previous cross-sectional research in the local area. These comparisons revealed good matches between current and past samples in broad patterns, but samples differed in specific detail. Comparison of correlations based on the subjective-probability method to those derived from traditional methods revealed that the former were consistently higher than the latter. Finally, the results involving the identification issue in cross-sectional data in which feedback loops appear were analyzed. (BM)