Up to 5% of Arkansas' population was not counted in the 2020 census, according to documents released Thursday by the U.S. Census Bureau.
The percentage of Arkansans missed by census efforts was the highest in the country, with five other states undercounting, the Census Bureau found in its post-mortem review.
The undercounts raised concerns about states missing out on their fair shares of $1.5 trillion the federal government will distribute to states in the next decade.
Gov. Asa Hutchinson in a Thursday statement said the new census figures could be used to adjust federal program funding.
"Significant federal dollars were spent in education and marketing efforts [for the census]," Hutchinson said through a spokeswoman. "It is one of the challenges for a growing rural state to assure the accurate count."
The governor's office didn't respond to questions about how much money the state spent on census efforts.
The Census Bureau's Post-Enumeration Survey, which gauges the success of the population-counting efforts of each decennial census, revealed six states undercounted and eight states overcounted. The survey collects answers to the same demographic questions on the census questionnaire to a sample of households and compares the two sets of results to determine what the census missed.
The full survey can be found at: www.arkansasonline.com/520censussurvey/.
Census undercounts signal people were not counted, while overcounts suggest they were counted more than once, such as children of divorced parents who share custody or people with vacation homes.
Arkansas' overall population grew from 2010 to 2020 even with the undercount, according to census data released in August. The state added 95,606 residents in the relevant decade, climbing from 2,915,918 to 3,011,524.
However, the survey released Thursday indicates that more than 150,000 additional Arkansans went uncounted.
Without the boost of 105,800 people in Benton and Washington counties, the state would have experienced its first drop in population since the 1960 census.
The Central Arkansas and Jonesboro metropolitan areas also recorded growth, while cities and counties throughout the Delta took some of the largest population hits, according to the 2020 data.
Thursday's news confirmed what mayors, county judges and local officials have been saying since the first census data began trickling out last year -- that people were missed.
In 2019, Hutchinson formed the 30-member Arkansas Complete Count Committee to promote 2020 census participation. The committee consisted of state, municipal and county government officials, as well as citizen and private sector representatives.
Committee Chairman George McGill, the mayor of Fort Smith and a former state legislator, could not be reached for comment Thursday.
Vice Chairman Shelby Johnson, director of the Arkansas Geographic Information Systems Office, said he hadn't had the opportunity to digest the Census Bureau's report as of Thursday afternoon.
Other members of the Complete Count Committee, as well as the Arkansas State Data Center within the Arkansas Economic Development Institute, declined to comment or did not respond to requests.
The onset of the COVID-19 pandemic in 2020 affected data collection for both the census and the Post-Enumeration Survey, said Tim Kennel, the Census Bureau's assistant division chief for statistical methods in the decennial statistical studies division.
Attempts to collect data for the Post-Enumeration Survey in 2020 saw low response rates, Kennel said in a Thursday webinar about the results.
Additionally, colleges and universities closed their campuses and conducted remote learning in 2020, meaning many students moved back home.
"This migration made it challenging to determine who should be included in the [survey] and who was out of scope because they should have been counted in college dorms or other group quarters," Kennel said.
Challenges aside, Arkansas' census promotion efforts were widespread, Johnson said.
"It would have been impossible to walk around in Arkansas at that time and not have seen information about the census, or seen a commercial on TV, or heard a commercial on the radio," Johnson said.
Arkansas, Florida, Tennessee and Texas did not direct as many resources as other states in encouraging residents to fill out census forms. Mississippi spent around $400,000 and Illinois allocated $29 million toward those efforts.
Arkansas' estimated 5.04% undercount was the largest of the six reported by the Census Bureau. Florida, Illinois, Mississippi, Tennessee and Texas also saw undercounts.
Delaware, Hawaii, Massachusetts, Minnesota, New York, Ohio, Rhode Island and Utah all overcounted their populations between 1.5% and 6.8%, according to the Census Bureau.
Any undercounts or over-counts in the remaining 36 states and the District of Columbia were not statistically significant, the bureau said.
Regionally, the bureau estimates a 1.85% undercount in the South and a 1.71% over-count in the Northeast.
While Florida and Texas saw smaller undercounts than Arkansas -- 3.5% and 1.9% respectively -- both states lost seats in Congress while the much less populous Arkansas did not.
Meanwhile, in Minnesota and Rhode Island, overcounts appear to have saved them from losing congressional seats.
Undercounted groups historically have been racial and ethnic minorities, renters and young children.
Thursday's news release did not break down by demographic traits how good of a job the 2020 census did at the state level, but a national report card released in March showed the Black population in the 2020 census had a net undercount of 3.3%, while it was almost 5% for Hispanics and 5.6% for American Indians and Native Alaskans living on reservations.
Those identifying as some other race had a net undercount of 4.3%. The non-Hispanic white population had a net overcount of 1.6%, and Asians had a net overcount of 2.6%, according to the results.
Information for this article was contributed by Michael Wines of The New York Times and Michael Schneider of The Associated Press.