Census Data Shows Differing Trends for Cities and Suburbs, Concerns Over Data Quality Remain


  • Dana Watters
August 18, 2021 - (5 min read)

Last Thursday, the Census Bureau released the highly anticipated redistricting data in accordance with Public Law 94-171. Complications related to the COVID-19 pandemic significantly shifted the timeline of data delivery and have left many government entities at the federal, state, and local levels concerned about the reliability and accuracy of the data. In addition, the Census Bureau’s application of a new disclosure avoidance system has raised concerns over bias that may inhibit redistricting in accordance with the Voting Rights Act of 1965.

Population and Housing Growth Concentrated in Cities

One notable takeaway is the disparity in population change between metropolitan, micropolitan, and suburban areas. Data show that the United States population has grown by 22.7 million since 2010. The 7.4% increase represents the second-lowest ten-year rate of growth in history, reflecting an overall trend of slowing population growth. 52% of counties lost population, and fewer counties and metro areas grew this decade than in previous ones. Much of the population growth was concentrated in metro areas, with 312 of the 384 U.S. metro areas seeing population gains. Eight of the 10 largest cities grew faster in this decade than the last; the biggest gains were in New York City and Houston, while Phoenix grew faster than any other city. Conversely, 72 U.S. metro areas saw population declines over the past decade, with the largest declines by percentage were Pine Bluff, AR and Danville, IL. 

Redistricting data has long been used to measure the diversity of the country, and this most recent release showed a population that is growing more diverse. The number of individuals who identify as two or more races (also known as the multiracial population) grew significantly since 2010, rising from 9 million to 33.8 million, a 276% increase. Multiracial or “in combination” populations across racial groups accounted for most of the overall changes in each racial category. The data also show that while the number of adults (18 and over) grew 10.1% in the past decade, the population under age 18 decreased by 1.4%.

Another key component of the P.L. 94-171 data release is housing information, which showed a 6.7% increase in the number of units since 2010 for a total of 140,498,736. This growth was not uniform throughout the country; just as population growth was concentrated in metropolitan areas, the average increase for counties that composed some part of a metropolitan or micropolitan area was 3.8%, while counties outside of these areas showed an average decrease of 3.9%. The percentage of housing units vacant in 2020 dropped to 9.7% (13,681,156 housing vacant units), down from 11.4% in 2010. Areas with large numbers of seasonal or vacation rentals, such as beach towns and ski resorts, had high vacancy rates, over 50% in some cases. Large metropolitan areas, meanwhile, had lower-than-average vacancy rates, with the lowest in Minneapolis (4.6%), Los Angeles (4.8%), Seattle (5.2%) and Portland (5.2%). 

Data Quality and the Impact of the Pandemic

One of the biggest questions raised by this release is the extent to which the pandemic impacted the quality of the data. COVID forced the suspension of traditional door-to-door enumeration for months, leading to a truncated non-response follow-up (NRFU) period. This process was itself made more difficult by shifting timelines, residents worried for their health, restrictions on entering group quarters such as nursing homes, and changes of primary residence in response to the pandemic, among other things. The Census Bureau has issued assurances that the results and data are “comparable to the population benchmarks” they have examined, but many local leaders and members of their communities are justifiably concerned about the impact that an inaccurate count may have on the allocation of trillions in federal funding over the next decade and on the redistricting process.

Adding to concerns about redistricting is the newly implemented disclosure avoidance system (DAS), the Census Bureau’s method for safeguarding the privacy of personal information by injecting “noise” into data. A recent Harvard University study came to the troubling conclusion that “the DAS-protected data are biased against certain areas, depending on voter turnout and partisan and racial composition” and “can still inaccurately estimate the number of majority-minority districts.” Among other conclusions, the authors found that the use of the 2020 DAS-protected data, compared with 2010 Census data, hindered the ability to draw districts of equal population, particularly for smaller districts such as state legislative and school board districts. The data, they found, also transfer population from racially mixed areas to racially segregated areas potentially leading to a distortion in the number of majority-minority districts. For cities and towns relying on accurate demographic information for their own local redistricting processes, bias resulting from DAS-injected noise at the block level stands to have a far greater potential impact than for redistricting processes at the state level.

We do not yet know all of the implications that the data—whether accurate or not—may have for cities, towns, and villages over the coming years. Local leaders may need to approach the 2020 data with more caution than prior years and follow updates from the Bureau on data quality more closely than they have in the past. Some localities may have to weigh whether to commence the Count Question Resolution or Population Estimate Challenge process, both of which can be costly and have limited capacity to deliver redress. This unique moment also reinforces the need for input from local leaders, who will have opportunities in the coming months to advocate on behalf of their communities to state and federal legislatures and to the Census Bureau itself. 

It is the goal of the National League of Cities to support local leaders in these efforts and in preparing for the 2030 census, however far off it may seem.

Want to Learn More?

Our Cities Count program provides technical assistance through monthly webinars, bringing together local leaders and subject matter experts, and will convene this Thursday, August 19th at 3pm EST to discuss the data release and answer questions on next steps. Submit questions in advance to censusrapidresponse@nlc.org

About the Author

Dana Watters

About the Author

Dana Watters is the Program Manager for Local Democracy Initiative’s Cities Count and Cities Vote programs at the National League of Cities.