The Empirical Curriculum is a descriptive account of the major features of change in student course-taking in postsecondary contexts between 1972 and 2000, with an emphasis on the period 1992-2000. To provide this account, it draws on three grade-cohort longitudinal studies that were designed and carried out by the National Center for Education Statistics, and within those studies, high school and (principally) college transcript records: (1) The National Longitudinal Study of the High School Class of 1972 (NLS-72), which began with a national sample of 22,500 12th graders in U.S. high schools in the spring of 1972 and followed them to 1986 (the postsecondary transcripts for 12,600 members of this cohort were gathered in 1984); (2) The High School and Beyond/Sophomore cohort (HS&B/So), which began with a national sample of 30,000 10th graders in U.S. high schools in 1980, and followed sub-groups of this cohort to 1992 (the postsecondary transcripts for 8,400 members of this cohort were gathered in 1993); and (3) The National Education Longitudinal Study of 1988 (NELS: 88/2000), which began with a national sample of 25,000 8th graders in U.S. schools in 1988, and followed sub-groups of this cohort to 2000 (the postsecondary transcripts for 8,900 members of this cohort were gathered in 2000).