Study: AZ likely to suffer worst Census undercount, lose congressional seat, if citizenship question added

Photo by David Maiolo | Wikimedia Commons/CC BY-SA 3.0

A new estimate shows Arizona’s total population could see an undercount of nearly 5% if a controversial citizenship question is added to the 2020 Census – and potentially miss out on adding a congressional seat and Electoral College vote.

That’s according to a study from Harvard University’s Shorenstein Center on Media, Politics and Public Policy, which The Washington Post compiled in state-by-state estimates.

The study surveyed about 9,000 Hispanic and non-Hispanic people with a form matching the one used by the U.S. Census Bureau and asked half of them, “Is this person a citizen of the United States?”

“We find that asking about citizenship status significantly increases the percent of questions skipped, with particularly strong effects among Hispanics, and makes respondents less likely to report having Hispanic household members,” the study concludes.

It estimated that ”asking a citizenship question may lead to an undercounting of Hispanics of between 5,761,284 and 6,382,820 in the 2020 Census.”

The Post’s analysis showed approximately 362,496 Hispanic Arizona residents (accounting for about 5% of the state’s total population) would be undercounted in 2020.

With this undercount, Arizona would not gain one seat in the U.S. House of Representatives as projected, according to the Post’s analysis.

Like any other community with a miscount, Arizona and its local governments would also lose millions in federal funding for social services, education and transportation projects. Besides determining political representation in Congress, Census data is also used to draw local political districts.  

The Trump Administration is pushing to include the question, “Is this person a citizen of the United States?” in the 2020 Census, arguing it is needed to help enforce the Voting Rights Act.

However, recent documents that came to light indicate that the addition of the question has purely political aims. Files that belonged to Republican redistricting expert Thomas Hofeller, who died last year, show that he believed – told the Trump administration – that adding the citizenship question would decrease responses by Hispanics, and thus would allow for the creation of congressional and legislative maps that “would be advantageous to Republicans and non-Hispanic whites.”

There are several lawsuits challenging the inclusion of the question, and the Supreme Court is expected to weigh in by the end of June.  

The decennial census hasn’t asked respondents about citizenship since 1950, but the smaller and annual American Community Survey has included it.

In the ACS from 2016, Arizona topped the list nationally of nonresponse rates to that question. Arizona’s nonresponse rate to the citizenship question was 9%, while the national average was 6%.

Another study estimates that more than 4 million people nationally are at risk of being undercounted, which could lead to the worst undercount of black and Latino people in the U.S. since 1990, according to NPR.

Cities and non-profits across the Arizona are working on outreach campaigns to ensure the 2020 census accurately reflects the state’s populations.

The Maricopa Association of Governments, Maricopa and Pinal counties, and three tribal governments recently launched the iCount 2020 campaign.

“We want to reach everyone,” said Laurie Berg Sapp, MAG’s communication project manager. “We really want to target those populations that have been undercounted in the past: populations like families with children five and under; those who know little to no English; low-income populations; students; and snowbirds.”

The City of Phoenix is also proposing to set aside $1.5 million for its next fiscal year for outreach related to the 2020 census.

“We cannot afford for any one group in our city to not participate,” said Albert Santana, census director for the city. “If one section of this gets undercounted we are all impacted. We are all in this together.”

Laura Gómez
Reporter Laura Gómez Rodriguez covers state politics and immigration for the Arizona Mirror. She worked for The Arizona Republic and La Voz Arizona for four years, covering city government, economic development, immigration, politics and trade. In 2017, Laura traveled the length of the U.S.-Mexico border for “The Wall,” the Pulitzer Prize-winning project produced by The Arizona Republic and USA Today Network. She was named Best Investigative Reporter by Phoenix Magazine in its 2018 newspaper category and has been honored by the Arizona Press Club for Spanish-language news and feature reporting. She is a native of Bogotá, Colombia and lived in Puerto Rico and Boston before moving to Phoenix in 2014. Catch her researching travel deals, feasting on mariscos or playing soccer.


  1. There is a fundamental problem with this read of the study in question, and thus with the Washington Post article and the conclusions cited in this article. The study looked at what percentage of respondents left the citizenship question blank, among respondents answering the initial question of how many people live in the household. The Washington Post then counted that as the “under-counted” percentage. But there are no blanks in a final official Census form. The Census Bureau follows up to either get an answer or to estimate citizenship (and other potential blanks) using other data. So once the respondent answers how many people are in the household, those people are counted — even if they initially leave the citizenship question blank. The actual undercount is the number of people who do not return the form at all AND who avoid all Census follow up questions AND for whom the Bureau’s efforts to estimate the number of people in the household either miss the household completely or under-estimate the number of people in the household.

  2. Actually considering illegal non-residents is OVERCOUNTING! They are not permanent residents of our country. I suppose not counting those who deplane at Sky Harbor should be given a census form to figure our population on a specific date. How about counting vacationeers at the Grand Canyon? Gee, we could give free transportation and lodging to thousands and count them. It would increase revenue sharing for ten years. Well worth the waste of taxpayer funds to cheat the purpose of the census.

  3. Albert Santana is right: All Arizonans will be negatively impacted if we don’t get an accurate count of our residents. Let’s hope the Supreme Court recognizes how odious the decision to add a citizenship question truly is. If they do not, and the question remains, perhaps our campaign should be to ask EVERYONE to refuse to answer that question. It will not be mandatory to do so.


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