The Census Bureau's OnTheMap tool is a web-based mapping application that shows where workers are employed and where they live. The application merges data from numerous sources, including Unemployment Insurance (UI) Wage Records, the Quarterly Census of Employment and Wages (QCEW) program, and LEHD Origin-Destination Employment Statistics (LODES). Longitudinal Employer-Household Dynamics (LEHD) data are the result of a partnership between the Census Bureau and U.S. states to provide high-quality local labor market information and to improve the Census Bureau's economic and demographic data programs.
A primary job is defined as the highest-paying public or private-sector job for an individual worker. Therefore, there is one worker for each primary job. The terms "primary jobs" and "workers" are interchangeable.