The Health and Retirement Study (HRS) is a long-running study that examines middle-aged and older adults in the US, producing data that is used both domestically and internationally. As a panel survey, HRS follows approximately 20,000 U.S. adults, some of whom have participated in the study for 30 years, through the retirement and aging process.

Founded in 1957, Life Course Development (LCD) aims to expand knowledge of social relationships across the lifespan and their implications for mental and physical health. LCD examines a wide variety of relationships, identifying the aspects of relationships that are most beneficial and/or harmful to health and whether these associations vary by demographic and contextual factors. With this knowledge, the program hopes to help in the design and implementation of intervention and prevention programs.