A lower court has denied Alabama's request to force the Census Bureau to move up the release of new redistricting data and stop plans for a different way of keeping people's information confidential.

Transcript

AILSA CHANG, HOST:

A new court ruling has set up another legal battle over the 2020 Census that is likely heading to the Supreme Court. This time, the fight is over the data used for redrawing voting districts, and it could cause major delays to upcoming elections around the U.S. NPR census correspondent Hansi Lo Wang joins us now from New York.

Hey, Hansi.

HANSI LO WANG, BYLINE: Hey, Ailsa.

CHANG: OK, so what does this new court ruling say exactly?

WANG: Well, the state of Alabama asked for an emergency court order that would have forced the Census Bureau to release the detailed 2020 census data about people's race and other demographic information that's used when redrawing voting districts - to release that data earlier than the bureau has been planning. The bureau's been on track to release this data by August 16, and Alabama wanted the court to stop the bureau from also using new privacy protections for keeping people anonymous in this detailed demographic data. And this new ruling by a three-judge court means the bureau can continue its plans to use these new privacy protections and stick with its schedule for releasing new redistricting data by mid-August.

CHANG: Wait. Tell us more about these protections. Like, how exactly has the bureau been planning to protect people's privacy in this redistricting data?

WANG: Well, the bureau has been developing a new way of keeping people's information confidential. It's based on a mathematical concept known as differential privacy. And it's important to note federal law prohibits the bureau from releasing personally identifiable information until 72 years after it's collected for the census. And bureau says it's trying to keep up with advances in computing and access to commercial data sets that can be cross-referenced and makes it easier to trace supposedly anonymized census to get back to a person. And the bureau concluded that a privacy protection system based on differential privacy is the best way to balance protecting confidentiality and keeping census data useful.

CHANG: So what's Alabama's argument? Like, why does the state oppose the Census Bureau's plan to protect privacy?

WANG: Alabama has been arguing that it will make the new redistricting data unusable for the redrawing of voting maps because of the way the bureau is planning to add noise or data for fuzzing the census results and the way the bureau is trying to smooth out the effects of adding that noise. Now, Alabama's argument, though, is citing early analysis of some preliminary test data, and bureau has since changed its privacy plans. And it says that its latest version - in a statement - quote, "ensures the accuracy of data necessary for redistricting and Voting Rights Act enforcement." So at this point, we'll have to keep watching this debate play out in court.

CHANG: Right. This is most likely not the end of the road legally, right?

WANG: Right, because federal law allows this three-judge court's rulings to be appealed directly to the Supreme Court. And this legal fight is keeping just a cloud of uncertainty over this data and the Census Bureau's privacy protection plans.

CHANG: Well, talk about that uncertainty. Like, how could it affect upcoming elections, you think?

WANG: Well, to prepare for upcoming elections, many local and state redistricting officials are waiting for new 2020 census data. They determine the areas future elected officials will represent - those maps. And some state and local governments have already been pushing back primary and general election dates. And these delays in getting the data out could also shrink the amount of time for public feedback on new voting maps. And, you know, the bureau says if the courts ultimately block its current privacy protection plans, the bureau will need six to seven months to work out alternative plans. And that would mean it's possible that 2020 census redistricting data may not be out until early 2022.

CHANG: Yeesh (ph). That is NPR's Hansi Lo Wang who covers the census for us.

Thank you, Hansi.

WANG: You're welcome, Ailsa. Transcript provided by NPR, Copyright NPR.