Autor, David H.; Patterson, Christina; Van Reenen, John - National Bureau of Economic Research - 2023
concentration. We document that the Herfindhahl index of local employment concentration, measured at the county-by-NAICS six … employment concentration trends is attributable to the structural transformation of U.S. economic activity: both sales and … employment concentration rose within industry-by-county cells; but reallocation of sales and employment from relatively …