In test data, the method known as “differential privacy” made smaller counties appear to have more people than they actually did at the expense of more populous counties. The findings reinforce concerns that differential privacy will lower the quality of the data used for redrawing congressional and legislative districts. The report is the latest warning about the Census Bureau's introduction of deliberate errors to protect privacy into the 2020 census data that will be used for redistricting later this year. Differential privacy adds mathematical “noise,” or errors, to the data to obscure any given individual’s identity while still providing statistically valid information. The Census Bureau says it is still formulating the details, but bureau officials have previously described trying to find “the sweet spot” between data confidentiality and data accuracy.

Source: ABC News April 05, 2021 18:23 UTC