“The decisions strike the best balance between the need to release detailed, usable statistics from the 2020 Census with our statutory responsibility to protect the privacy of individuals’ data,” said Ron Jarmin, acting director of the Census Bureau. “They were made after many years of research and candid feedback from data users and outside experts -– whom we thank for their invaluable input.”
University of Minnesota demographer Steven Ruggles, who had raised accuracy concerns about earlier versions, said Wednesday that the epsilon in the final guidelines is now so high it won't offer much privacy protection.
“The inventors of differential privacy regard such a high epsilon as pointless," Ruggles said.
The state of Alabama sued in an effort to stop differential privacy from being used at all on the redistricting data, claiming it would produce inaccurate numbers, and a panel of three judges could make a decision any day.
The Census Bureau says more privacy protections are needed than in past decades, as technological innovations magnify the threat of people being identified through their census answers, which are confidential by law. Computing power is now so vast that it can easily crunch third-party data sets that combine personal information from credit ratings and social media companies, purchasing records, voting patterns and public documents, among other things.
The redistricting data is expected to be released in mid-August. In September, the Census Bureau will release test data from the 2010 census with differential privacy applied using the final guidelines so researchers can examine how accurate it is.
Princeton University researchers Ari Goldbloom-Helzner and Sam Wang on Wednesday said in an email that the Census Bureau was being responsive to concerns raised and targeting accuracy in smaller jurisdictions. Studying an earlier version with greater privacy restrictions, the two researchers had previously said applying differential privacy had no practical impact on redistricting data.
“At this point my team is confident that the data will be fully fit for redistricting," Wang said.
Follow Mike Schneider on Twitter at https://twitter.com/MikeSchneiderAP