The NELS:88, which began with an 8th grade cohort in 1988, provides trend data about critical transitions experienced by young people as they develop, attend school, and embark on their careers. Data were collected from students and their parents, teachers, and high school principals and from existing school records such as high school transcripts. Data from school transcripts include information that is contained on the student high school record—i.e., courses taken while attending secondary school; information on credits earned; year and term a specific course was taken; and, final grades. When available, information on class rank and standardized scores is also collected. Once collected, information (e.g., course name, credits earned, course grades) is transcribed and standardized (e.g., credits and credit hours standardized to a common metric) and can be linked back to the student’s questionnaire or assessment data. Additionally, cognitive tests (math, science, reading, and history) were administered during the base year (1988), first follow up (1990), and second follow up (1992). Third follow up data were collected in 1994. All dropouts, who could be located, were retained in the study. A fourth follow-up was completed in 2000, including a postsecondary student transcript data collection. NELS collect data from students, teachers, school administrators, and parents.