The purpose and goals of the study have evolved over the life of the project. The original study was launched in 1962 as a prospective study of childbearing. The original interviews collected a wide range of information useful for predicting subsequent childbearing decisions, while the follow-up data collections through 1966 measured subsequent fertility experience. In 1977, the purposes of the study were expanded to investigate employment, divorce, and changing family attitudes while at the same time retaining the earlier emphasis on childbearing decisions.

In 1980, the study shifted its emphasis to include the children in the family and how they were influenced by the homes in which they were reared. The project became interested in the ways in which the parental family influenced the attitudes, values, experiences, and plans of the children. Of particular interest were the children's attitudes and experiences in the domains of marriage, childbearing, school, work, living arrangements, and family relationships. The 1980 wave of interviews with the children was also designed to be the first wave of a prospective study of the determinants of variations in the ways children made the transition to adulthood. The 1985 survey used a life history calendar (LHC) to obtain from the young adults retrospective data about their monthly living arrangements, cohabitation, marriage, childbearing, schooling, and work. In 1993, the data were extended to cover the experiences of the children and their families as the children matured into their early thirties. A life history calendar was again used.