County-Level Drivers of Prime-Age Population Growth or Decline in the United States

The availability of prime-age workers has emerged as a central challenge for communities and economic developers across the United States, intensified by an aging population, demographic shifts, and the disruptions of the COVID-19 pandemic. This study examines the factors associated with growth or decline in prime-age working residents at the county level between 2013 and 2023, using first-differenced OLS regressions with state-clustered standard errors across 3,095 U.S. counties. Drawing on data from the American Community Survey and the USDA Economic Research Service, the model incorporates twelve variables spanning structural characteristics and time-varying local conditions, including three innovative metrics: digital distress, entrepreneurial efficiency, and a caring stress index. Results indicate that metropolitan status, housing cost pressures, work-from-home prevalence, and natural amenities are positively associated with prime-age population growth, whereas an aging population and high caring stress are the strongest negative predictors. By introducing the caring stress index, this study extends spatial equilibrium theory and advances the empirical understanding of prime-age labor supply dynamics. For practitioners, the findings suggest that, as communities compete for a shrinking pool of prime-age workers amid accelerating demographic change and significant place-based investments, workforce development strategies need to broaden to include caring infrastructure and remote-work access, in addition to traditional metrics such as educational attainment. This broader focus more effectively interconnects the drivers of community competitiveness.