16 states back Alabama's challenge to Census privacy tool

FILE - This March 19, 2020, file photo, shows an envelope containing a 2020 census letter mailed to a U.S. resident. On Wednesday, March 24, 2021, a federal judge dismissed a lawsuit filed by the state of Ohio that tried to get the U.S. Census Bureau to provide data used for drawing congressional and legislative districts ahead of its planned release. (AP Photo/Matt Rourke, File)
FILE - This March 19, 2020, file photo, shows an envelope containing a 2020 census letter mailed to a U.S. resident. On Wednesday, March 24, 2021, a federal judge dismissed a lawsuit filed by the state of Ohio that tried to get the U.S. Census Bureau to provide data used for drawing congressional and legislative districts ahead of its planned release. (AP Photo/Matt Rourke, File) (Copyright 2020 The Associated Press. All rights reserved.)

ORLANDO, Fla. – Sixteen other states are backing Alabama's challenge to a statistical method the U.S. Census Bureau is using for the first time to protect the privacy of people who participated in the 2020 census, the nation's once-a-decade head count that determines political power and funding.

A federal judge on Monday allowed the 16 states to file a brief in a support of a lawsuit brought by Alabama last month. The suit seeks to stop the Census Bureau from applying the method known as “differential privacy" to the numbers that will be used for redrawing congressional and legislative seats later this year.

The states supporting Alabama's challenge are Alaska, Arkansas, Florida, Kentucky, Louisiana, Maine, Mississippi, Montana, Nebraska, New Mexico, Ohio, Oklahoma, South Carolina, Texas, Utah and West Virginia. Maine and New Mexico have Democratic attorneys general, while all the other states have Republican ones.

A three-judge panel in federal court in Alabama is hearing the case, which could go directly to the Supreme Court if appealed.

Differential privacy adds mathematical “noise,” or intentional errors, to the data to obscure any given individual’s identity while still providing statistically valid information.

Bureau officials say the change is needed to prevent data miners from matching individuals to confidential details that have been rendered anonymous in the massive data release, which is expected as early as August. It will be applied to race, age and other demographic information in geographic areas within each state.

The confidentiality of census responses is protected by federal law.

“It’s a statistical technique that is intended to protect people’s privacy ... There can be privacy hacks today that technologically weren’t possible 10 years ago,” said Department of Commerce Secretary Gina Raimondo last week during a White House briefing. “So in order for us to keep up with that and protect people’s privacy, we have to implement new techniques, and this is one of those new techniques.”