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City of Chicago Census and Data Collaboration

Chicago, IL, August 17, 2017: The L Train, or elevated train, runs through downtown Chicago during rush hour. Chicago's CTA offers trains and buses for commuters who work and live all over the city.
Collaborating with the City of Chicago to review their 2020 Census count of Group Quarters and population estimates
  • Client
    The City of Chicago’s Chief Equity Officer
  • Dates
    March 2023 - December 2023


The City of Chicago wants to ensure its population counts and estimates are accurate.

To make sure that the 2020 Census counts are accurate, the US Census Bureau is running a Post-Census Group Quarters Review challenge program. The program allows cities across the United States to submit for review group quarters population counts they believe may have been enumerated incorrectly or missed. The City of Chicago experienced significant environmental challenges to enumeration during the 2020 Census, including the COVID-19 pandemic and unrest related to protests. The City wants to make sure that the enumeration of their Group Quarters population is as accurate as possible given these events.


NORC’s expertise with administrative records helps the City of Chicago ensure an accurate population count.

In preparation for the City of Chicago’s response to the Post-Census Group Quarters Review challenge program, the NORC team acquired, cleaned, harmonized, and geocoded information about facilities in the City that meet Census Bureau definitions of group quarters (such as nursing homes, dorms, and residential treatment centers). Methodological experts created a frame and identified gaps between it and Census records. A vetting team verified facilities that potentially have been undercounted.

For the Population Estimates challenge program, NORC methodologists are evaluating the Census Bureau methodology for estimating the 2022 Chicago population. Using multiple data sources, NORC is developing alternative methods to estimate the City’s population and will recommend the best method for the City. In addition, through this partnership NORC’s demographic, statistical, and data science experts are providing ongoing technical consultation to the City as it prepares for the 2030 Census. Early planning activities may include enhancement of the methodology used for population estimation, establishment of a master housing unit database, data harmonization, and dissemination.


An accurate population count advances the City of Chicago’s equity efforts.

NORC identified several hundred group quarters facilities that may have been missed during the 2020 decennial census. These facilities will be validated and a final list submitted to the Census Bureau for review. Accuracy of the decennial census count is imperative because the City relies on census data at every level of planning and policy-making. The project is also directly aligned with the City’s efforts to advance equity in how it provides services and resources to residents.

“As a longstanding Chicago-based organization, NORC is pleased to provide cutting edge methodological expertise in support of the City’s efforts to ensure an accurate population count.”

Principal Research Director

“As a longstanding Chicago-based organization, NORC is pleased to provide cutting edge methodological expertise in support of the City’s efforts to ensure an accurate population count.”

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