Why States Should Wait for Census Data to Draw Voting Districts

Published in Brennan Center News on

It would be a mistake to create new voting maps using the American Community Survey rather than the full 2020 Census results

Census data should be used to draw final redistricting maps because census data is based on an actual count of the U.S. population and provides greater geographic specificity and accuracy than ACS data. ACS estimates, by contrast, are just that: estimates that come with the margins of error associated with any survey. That margin of error makes it hard to draw maps with the population precision required by the Constitution. Indeed, the Census Bureau itself says that the ACS is better suited to providing demographic information than total population figures.

Plus, as mentioned above, the smallest unit used for reporting ACS data is significantly larger than the units used to report census data. This also makes it more difficult to use ACS data to satisfy the constitutional requirement that districts have roughly the same number of people and at the same time satisfy other legal requirements for redistricting. For these and other reasons, the Brennan Center joined Asian Americans Advancing Justice (AAJC), MALDEF, and over 50 other civil rights and good government organizations in releasing a statement explaining why ACS data should not be used to draw final district maps.