Over 90 organisations including the Insights Association and the American Statistical Association co-signed a letter to the chairs and ranking members of the Senate and House appropriations committees, calling for the Census Bureau to receive $1.57bn in funding – the level recommended by the Senate appropriations committee in negotiations over the final 2025 fiscal year (FY) funding.

The House bill would provide the Bureau with $1.543bn – $28m less than the agency’s 2024 funding level and lower than the Administration’s budget request.

The letter to appropriators said: “This is exactly the wrong time in the ramp up to the 2030 Census for Congress to cut funding for the U.S. Census Bureau. The agency needs robust, sustained funding, especially at this point in the decennial census planning process, to proceed with critical planning activities that will ensure the success of the 2030 Census.”

Census Project co-director Howard Fienberg said: “The funding levels recommended by the House and Senate appropriations committees pose dramatically different outlooks for the Bureau.”

In the letter, the authors said funding cuts leading up to the 2020 head count led to operational and accuracy challenges.

“When Congress failed to meet the Administration’s request for 2020 Census planning in Fiscal Years 2012-2017, the Census Bureau had to cancel every planned test in a rural area and on American Indian reservations, including two of three dress rehearsal sites in 2018. After the census, the Bureau’s check of its work showed a net undercount of 5.64 percent on American Indian reservations, and a net undercount of 2.58 percent in areas counted with a modified census packet delivery method called “Update/Leave,” which is used primarily in rural areas,” the letter said.

Census Project co-director Mary Jo Mitchell said: “Mid-decade funding is critical to planning, researching and testing the hundreds of operations that are critical to a complete and accurate count of everyone in the nation.”

The letter also expressed concerns regarding potential policy provisions proposed in the House CJS appropriations bill that the groups said could “severely undermine the ability of the agency to deliver high-quality, accurate data”. This relates to a section of the bill that says funds may not be used to enforce mandatory compliance or to inquire more than twice for voluntary compliance with any survey conducted by the Census Bureau.