Can you tell me about the controls used in the American Community Survey (ACS)?

The American Community Survey (ACS) uses independent estimates of population and housing units from the Population Estimates Program as survey controls.

• For the Group Quarters (GQ) population, estimates are controlled for total GQ population by major GQ types (e.g., adult correctional facilities, nursing homes, college dorms, etc.) within states.
• For total resident population and for housing units, the ACS is controlled for incorporated places, minor civil divisions (MCD), and counties (or groups of smaller counties).
  • At the incorporated place and MCD level, the Census Bureau controls only for total population and the number of housing units.
  • At the county (or group of small counties) level, the Census Bureau also controls for the total population's base demographics (race, age, sex, and ethnicity).
• The statistical weights defined after the application of controls are then used to produce the totals and characteristic data, including base demographics, for all geographic areas.

Learn more about the weighting methodology in the Accuracy of the Data document.