The decennial count of America’s population drastically undercounted the number of people who live in six states, the U.S. Census Bureau said Thursday, putting at risk billions of dollars in potential federal funding over the next decade.
Most of the states that suffered severe undercounts are in the South: A follow-up survey the bureau conducted after the 2020 count showed Arkansas’s population was undercounted by just over 5 percent, the populations of Mississippi and Tennessee were undercounted by more than 4 percent and Florida’s population came in almost 3.5 percent short.
The census undercounted populations in Texas and Illinois by 1.9 percent, the Bureau said in a press briefing Thursday.
The populations in eight states — Delaware, Hawaii, Massachusetts, Minnesota, New York, Ohio, Rhode Island and Utah — were overestimated in the decennial count, the Bureau said.
Hawaii’s population was the most overcounted, by nearly 6.8 percent.
The new figures will not change congressional apportionment, the bureau said.
The bureau did not offer demographic details of the populations that were undercounted, but census experts have long worried that low-income and minority populations are the most likely to be missed.
In this decade’s census, observers were most concerned that Hispanic Americans might be left out of the count after the Trump administration attempted to add a citizenship question to the survey.
Tim Kennel, who led the post-enumeration survey, said the transition from paper counts to an internet-based system, first used in the 2020 census, had led to lower error rates than in previous years.
“Many of the innovations were successful. The internet self-response was widely used,” Kennel said.
The decennial census is used for allocating money from hundreds of federal programs to the states, making correct counts crucial for states that depend on money for everything from school systems to wildfire preparations.
The results of post-enumeration surveys have varied widely over the decades. Twelve years ago, no state experienced a statistically significant overcount or undercount, Kennel said. In 2000, the populations of 22 states were overcounted, while the population of Washington, D.C., was undercounted.
People might be undercounted when they refuse to respond to the census or follow-up efforts to contact them. They might be overcounted in second homes, or if children of divorced parents are counted at both parents’ homes, Kennel said.