This is the second phase of a longitudinal study of academic science and engineering research groups in the United States. The study is concerned with: 1) the social organization, functioning, and life course of research groups; 2) the research performance of the group, including properties of the group's research system (that is, the set of materials, methods, instruments and ideas used in the research process), its risk profile, and published productivity; 3) the influence of group characteristics on the work-related attitudes, values, and behaviors of member scientists and engineers.