The middle-school and high-school years are a period of change and crystalization in terms of life goals, disciplinary and course preferences, and social and political attitudes. The literature provides a number of cross-sectional descriptions and models concerning cognitive and attitudinal development during adolescence and young adulthood, but there are no longitudinal data available to study these processes. The proposed longitudinal study will examine the (1) development of interest in science and mathematics, (2) the growth of scientific literacy, (3) the development of attentiveness to science and technology issues, and (4) the attraction to careers in science and engineering among two national cohorts of adolescents and young adults. One cohort will begin with a national sample of 3,000 seventh graders and follow them through the 10th grade. The second cohort will begin with a national sample of 3,000 10th graders and follow them for the next four years through the first full year after high school. Data will be collected from students, teachers, counselors, principals, and parents. A purposive sample of two or three school districts with exemplary elementary school science and mathematics education programs will be selected and comparable data will be collected in these districts. The analysis will consist of a series of expanding multivariate developmental models that will seek to understand cognitive and attitudinal growth and change in the context of family, school, and peer influences. Each wave of data collection will provide an opportunity to examine cognitive and attitudinal change measures in an increasingly rich context of previous measures. Periodic reports will be issued with each cycle of data collection and the data will be made available to other scholars on a timely basis. The first phase of the project, being funded at this time, provides approximately 15 months for instrument development and pilot testing, for sample selection, for monitor selection and training, and for working with the research advisory committee.