Commerce Secretary Raimondo defends census privacy method

FILE - This March 19, 2020, file photo, shows a 2020 census letter mailed to a U.S. resident. Alabama on Wednesday became the second state to challenge the U.S. Census Bureau's decision to delay by six months the release of data used for redrawing congressional and legislative districts, as it took aim at the accuracy of a privacy protection system that it alleged is holding up the process.(AP Photo/Matt Rourke, File) (Copyright 2020 The Associated Press. All rights reserved.)

Commerce Secretary Gina Raimondo on Wednesday defended a controversial privacy technique being used by the U.S. Census Bureau in the 2020 census, a method the agency promised would only make small changes to actual numbers in counts of racial and ethnic groups.

The technique called “differential privacy" adds mathematical “noise,” or 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 expected as early as August. It will be applied to race, age and other demographic information in geographic areas within each state.

Speaking at a White House briefing, Raimondo said the method was “justified."

“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,” Raimondo said. “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.”

The Census Bureau said it is still formulating the details, but bureau officials have previously described trying to find “the sweet spot” between data confidentiality and data accuracy.

Last month, the state of Alabama and Alabama politicians sued the Census Bureau and the Commerce Department, which oversees the statistical agency, claiming differential privacy will result in inaccurate data.

On Monday, a pair of civil rights groups also raised concerns about differential privacy in a report.