Judges hear arguments over contentious Census privacy tool

FILE - Rows of homes, are shown in suburban Salt Lake City, on April 13, 2019. Utah is one of two Western states known for rugged landscapes and wide-open spaces that are bucking the trend of sluggish U.S. population growth. The boom there and in Idaho are accompanied by healthy economic expansion, but also concern about strain on infrastructure and soaring housing prices. (AP Photo/Rick Bowmer, File)
FILE - Rows of homes, are shown in suburban Salt Lake City, on April 13, 2019. Utah is one of two Western states known for rugged landscapes and wide-open spaces that are bucking the trend of sluggish U.S. population growth. The boom there and in Idaho are accompanied by healthy economic expansion, but also concern about strain on infrastructure and soaring housing prices. (AP Photo/Rick Bowmer, File) (Copyright 2019 The Associated Press. All rights reserved)

MONTGOMERY, Ala. – The fight over whether the U.S. Census Bureau can use a controversial statistical technique to keep people's information private in the numbers used for drawing political districts on Monday went before a judicial panel that must decide if the method provides enough data accuracy.

A panel of three federal judges heard arguments on whether the method known as “differential privacy” meets the federal legal requirement for keeping private the personal information of people who participated in the 2020 census while still allowing the numbers to be sufficiently accurate for the highly partisan process of redrawing congressional and legislative districts. Differential privacy adds mathematical “noise,” or intentional errors, to the data to obscure any given individual’s identity while still providing statistically valid information.

Because a panel of three federal judges will decide the matter, any appeal of the lawsuit brought by the state of Alabama could go straight to the Supreme Court.

Separately, another lawsuit brought by Alabama over the 2020 census was dismissed Monday at the request of the state. The lawsuit had tried to force the Census Bureau to exclude residents who are in the country illegally from the numbers used for divvying up congressional seats among the states. Alabama claimed it would lose a congressional seat if those residents were included, but the Cotton State defied expectations by keeping its seventh seat when the apportionment numbers were released last week. Former President Donald Trump issued a directive attempting to do the same thing, but President Joe Biden rescinded it when he took office in January.

In the lawsuit over the statistical method, Alabama and three Alabama politicians sued the Census Bureau earlier this year after the agency decided to delay the release of data used for drawing the political districts. Normally, the redistricting data is released at the end of March, but the Census Bureau pushed the deadline to sometime in August, at the earliest, because of delays caused by the coronavirus pandemic.

Alabama claims the delay was caused by the bureau's attempt to implement differential privacy, which the state's attorneys say will result in inaccurate redistricting numbers. At least 16 other states back Alabama's challenge, which is asking the judges for a preliminary injunction to stop the Census Bureau from implementing the statistical technique. Alabama also wants the agency to release the redistricting data by July 31.

Alabama Solicitor General Edmund LaCour told the judges that the Census Bureau should return to a previous method for protecting privacy where easily identifiable characteristics in a household are swapped with data from another household.

“Small changes matter when you are dividing up power," LaCour said.