Apr 14, 2023 - News

New Illinois population census data questioned

Change in Illinois population, 2020 to 2022
Data: U.S. Census; Map: Kavya Beheraj/Axios

Illinois' population shrank by 1.6% from 2020 to 2022, per new U.S. Census Bureau data.

Yes, but: An Illinois congressman is questioning the latest numbers and the federal agency, which he says is fueling "misleading narratives" with its flawed data.

Why it matters: The data can greatly affect Illinois' level of federal representation and more than a $1 trillion in federal funding over the next decade.

The big picture: The past few years have been especially turbulent for population trends, with the COVID-19 pandemic affecting birth and death rates, interstate and international migration, and more, Axios' Alex Fitzpatrick and Kavya Beheraj report.

By the numbers: According to the new estimates, Kendall County grew the most, by nearly 4% from 2020 to 2022.

  • Alexander County in far southern Illinois shrank by 6%.
  • Cook County supposedly saw a 2.9% decline.

Flashback: Census population estimates have proven unreliable in the past.

  • 2020 census figures estimated that Illinois had lost about 18,000 residents since 2010.
  • Then, last spring, the Census Bureau declared that, oops, the state had actually gained 250,000 people after conducting a post-enumeration survey to measure the census' accuracy.
  • Illinois was among 14 states in which the 2020 census undercounted or overcounted populations at a statistically significant rate. The agency blamed "challenges such as conducting fieldwork during the COVID-19 pandemic," among other issues.

What they're saying: Rep. Raja Krishnamoorthi has been urging the Census Bureau to update its methodology. He sent a letter to the bureau in December and then another two weeks ago, but nothing has changed.

  • "I'm disappointed that the Census Bureau has still not updated its methodology for population projections, even after announcing in May 2022 that its own research showed that Illinois' population was undercounted in the 2020 Census and in the years leading up to it," Krishnamoorthi tells Axios.
  • The Census Bureau did not respond to Axios' requests for comment.

What we're watching: Krishnamoorthi and other lawmakers have suggested, among other things, incorporating data from the PES into their population projections.

  • But in a February letter, the bureau said December 2023 would be the earliest that adjustments to the estimates could be made.

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