The Longitudinal Study of Generations research project began in 1971 as a survey of intergenerational relations among 300 three-generation California families: grandparents (then in their sixties), middle-aged parents (then in their early forties), and grandchildren (then aged 16 to 26).

The purpose of the study is to investigate what changes and what stays the same in intergenerational relations of the family as the decades pass, and with the aging of each generation, to explore how these changes impact on the well-being of individuals within the family.

The study has broadened since then to include a fourth generation, the great-grandchildren of these same families, and further surveys in 1985, 1988, 1991, 1994, 1997 and 2001. The research is funded by the National Institute on Aging.