Panel Study of Income Dynamics (PSID) The PSID is the world’s longest‑running longitudinal household panel, launched in 1968 by the Institute for Social Research at the University of Michigan (originally directed by James S. House). It began with a nationally representative sample of 5,000 U.S. families (≈ 18,000 individuals) and has followed the original respondents and their descendants for more than five decades. The core questionnaire collects exhaustive information on household composition, earnings, employment, wealth, assets, consumption, health, education, marriage and childbearing, as well as a range of supplemental modules (e.g., the Child Development Supplement, Transition into Adulthood Study). By 2024 the study comprises over 39 waves and roughly 10 000 families (≈ 25 000 individuals), with annual re‑interview response rates of 96–98 %. Purpose & use cases – PSID was created to examine economic mobility, poverty dynamics, wealth accumulation, labor‑market behavior, health trajectories, and intergenerational transmission of advantage. It is widely used by economists, sociologists, demographers, public‑policy analysts, and health researchers to test theories of income dynamics, evaluate social programs, and model long‑term outcomes. Key features / unique aspects – - Genealogical design: original respondents and all their descendants are tracked, enabling true inter‑generational analysis. - Breadth of content: over 1 000 variables per wave covering income, wealth, employment, health, education, family structure, and more. - High panel retention: unprecedented response rates ensure minimal attrition bias. - Public‑use and restricted files: data are freely downloadable in multiple statistical formats, with a flexible online Data Center that lets users create custom variable sets. These characteristics make PSID an unparalleled resource for studying the long‑run dynamics of income, wealth and well‑being in the United States.