When the Census Bureau formally kicks off this decade’s round of redistricting on Thursday with the release of detailed data from the 2020 count, it will set the stopwatch ticking for states to draw new congressional maps.

Colorado started its redistricting process earlier this summer, since it faces an Oct. 1 deadline to draw its new congressional and legislative boundaries. But several other states, including Connecticut, Iowa and Ohio, actually face earlier deadlines. The upcoming data release now creates a scramble among nearly every state to finish its maps before primaries start up next year, and for advocates for different groups of voters to try to keep up with them.

“We know in a number of states that very shortly after census data drops, that the redistricting process is going to begin, the maps are going to start getting released and that folks are going to have to start responding to them almost immediately,” said Adam Podowitz-Thomas, senior legal strategist at the Electoral Innovation Lab at Princeton University.

The hustle is happening because census data is being released late. For the first time ever, the agency missed its April 1 statutory deadline to release demographic details at the hyperlocal level due to the pandemic and various decisions made by the Trump administration.

In late April, the Census Bureau released apportionment population totals — used to reshuffle the 435 seats in the House — several months late. Changes over the past decade led to Texas gaining two seats, while Colorado, Florida, North Carolina, Montana and Oregon each gained one. California, Illinois, Michigan, New York, Ohio, Pennsylvania and West Virginia each lost a seat.

Thursday’s release also provides the first look at whether last year’s count missed members of minority groups. Arizona, along with Texas and Florida — other states with large Hispanic populations — fell short of expectations in apportionment, resulting in smaller gains in congressional seats than projected, or none at all.

[Census misses create worries of Hispanic undercount]

The Census Bureau is providing the data first in so-called “legacy format.” States and political parties generally have access to expensive, proprietary software they can use to start making maps right away. But the format can be harder for laypeople to process.

An easier-to-read “tabulated” version is due in September.

But groups seeking to increase transparency and civic engagement in the process plan to start analyzing the data and releasing their own, more readable versions almost immediately.

“There is a nontransparent process … done behind closed doors, and that leads to gerrymandering, leads to the building of districts where there is no competition, and where an individual or an entire party or other group may gain an advantage,” said Sam Wang, director of the Princeton Gerrymandering Project. “We’ve been operating on a different track, and this new track is really something that’s come up in the last five years or so. It’s the possibility that citizens and reform groups can talk back.”

Getting the data early and in a more readable format is especially important to minority communities who need accurate population estimates to support their arguments for where district lines should be drawn to represent their shared interests, said Scott Martinez, a partner at Martinez and Partners law firm who drew congressional maps that were adopted by the courts in Colorado in 2001 and 2011.

The Census Bureau had planned to release the redistricting data as late as Sept. 30 before arriving at a mid-August date amid litigation with Ohio and Alabama.

Those two lawsuits are currently in a holding pattern pending the release of redistricting data. Alabama also challenged the agency’s new privacy rules, which it says will make the data too inaccurate for redistricting.

[Census results start wave of litigation over new maps]

The agency has argued that the new privacy rules, which change small portions of the data following an algorithm, are needed to protect individual responses in the era of big data. However, agency officials have acknowledged that the process can produce inaccuracies and impossibilities at the census block level — the smallest level of geography used for legislative maps.

Alabama may revive its suit over the data accuracy following Thursday’s data release.

Litigation has already started in several states over new maps. Democratically aligned groups in Pennsylvania, Michigan and Louisiana have sued over the process. The parties have split control over state government in each of those states, making a deadlock over new maps likely.

Researchers will use Thursday’s results to gauge the accuracy of the count. Additionally, the American Statistical Association and the Committee on National Statistics plan on releasing reports about the accuracy of census results later this year.

In addition to redistricting and apportionment, census results help guide more than $1.5 trillion in federal spending every year.