A study examined eight local consortia identified as mature Tech Prep implementers. The four-year research used a mixed-method longitudinal design involving repeated field visits, short and long interviews of key stakeholders, classroom observations, and document review and analysis. About 4,700 Tech Prep and non-Tech Prep participants were selected for a causal-comparative study of students' educational and employment outcomes, with 2 or 3 panels of high school graduates from 4 academic years per consortium. Mid-point findings showed Tech Prep centered on secondary education with goals and policies broadening and target populations shifting toward all students; consortia increasingly linked Tech Prep to state-level efforts to raise academic standards and enhance academic course-taking; core curriculum occurred in many forms, including starting at grade 9 rather than 11 and extending to the bachelor's degree; students' math course-taking varied across sites; teacher and counselor training was a prominent element in all consortia; preparatory services were conceptualized and implemented in different ways; all consortia experienced an increase in Tech Prep student enrollment; at least 65 percent of Tech Prep participants enrolled in some form of postsecondary education; and Tech Prep participants were more likely to be working. (Case studies of each consortium are provided. (Contains 17 references.) (YLB)