In the American Community Survey (ACS) data products, I see "*****" in the margin of the error column. The footnote tells me that this is a controlled estimate. What does this mean?

Controlled estimates are not subject to sampling variability because they are made to conform to official intercensal estimates from the Census Bureau's Population Estimates Program (PEP). The PEP annually produces estimates of totals by sex, age, race, and Hispanic origin that are controlled to be equal to population estimates by weighting areas, such as counties, incorporated places, and minor civil divisions (MCDs). Learn more about ACS weighting methodology in the Design and Methodology Report and the Accuracy of the Data documentation.