Federal law requires the Census Bureau to protect the identities of individual respondents to each decennial census for 72 years.
By Jeremy Duda | Arizona Mirror
A new effort by the U.S. Census Bureau to protect people’s privacy could make it harder for the Arizona Independent Redistricting Commission to draw districts primarily composed of people of color that will withstand litigation under the Voting Rights Act.
Federal law requires the Census Bureau to protect the identities of individual respondents to each decennial census for 72 years. In order to meet that requirement in the face of computing and other technological advances that make it easier to glean individual identities from census data, the bureau began using a system known as differential privacy for the 2020 census.
Differential privacy is a mathematical system that uses arbitrary changes in data to prevent the identification of individuals within a dataset. What that means for redistricting is that the Census Bureau will add “noise” to change and obscure some data in order to prevent people from using census data to identify individuals. For example, if all residents of a census block are white except for one who is Latino, that person would be easily identifiable using census data. Differential privacy would obscure that information so that the person couldn’t be identified individually.
A federal appellate court last month rejected a request by the state of Alabama to bar the Census Bureau from using differential privacy in census data. The appellate court also rejected the state’s request that the bureau be forced to move up the release of the census data that states need for redistricting. The bureau now plans to release that data, in an archaic but usable format, on Aug. 16.
The commission on Tuesday heard competing presentations from two redistricting efforts about the effect that differential privacy will have on its efforts.
