A Nationally Representative Household Panel Survey (NRHPS) would represent a natural extension into the mid-21st century of the development of repeated cross-sectional and then longitudinal/panel household surveys that have constituted major resources for developments in social science and social policy since World War II. Although an inherently expensive endeavor, it would keep the U.S. comparable to and competitive with similarly wealthy nations that have already developed NRHPSs. An NRHPS may be the most cost-effective way to generate the data needed for advancement in social science and social policy because such progress requires data on a much wider range of attributes of the same individuals, households, and their environments than are currently available in existing surveys. These surveys tend to be specialized by scientific disciplines, substantive/policy areas, and/or segments of the population, and thus preclude the kind of thinking and data necessary across disciplines, substantive policy areas, and segments of the population that are most needed in both social science and social policy. To be a cost-effective vehicle for such purposes an NHRPS must: (1) create integration and synergy across disciplines, substantive areas, and population subgroups; (2) cost-effectively meet scientific and logistical challenges; and (3) foster and utilize scientific and methodological innovations.