Recommended contents for a longitudinal, population-representative study of health, retirement, and aging

ObjectivesGiven global trends in population aging, there is a critical need for data resources to deepen the scientific understanding of individual and population aging. Understanding the correlates and consequences of population aging can yield not only biological but also social, demographic, and institutional insights, which can inform the development of more comprehensive, evidence-based policies and programs. We aim to provide recommendations for key content and other considerations in developing such data resources.MethodsThe U.S. Health and Retirement Study (HRS) is a model study, presenting an exemplary research design with evolving, innovative content. Building on the HRS protocol, there have been substantial efforts to adapt and harmonize the study protocol worldwide over the past two decades. We draw insights from experience in harmonizing aging studies for international comparisons and suggest recommendations for developing scientifically sound and cross-nationally comparable data resources.ResultsOur recommendations include prioritizing appropriate sampling strategies to obtain longitudinal and population-representative data and ensuring the inclusion of core content domains to enable the study of aging processes at the individual and population levels, with particular focus on the dynamic associations between health, economic status, and social engagement.DiscussionRecommendations can guide the appropriate design of future international comparative research. Measurement challenges across key content domains, along with the need to accurately capture contextual factors such as policies and environments that influence health and socioeconomic outcomes, require deliberate consideration.