Skip to main content

City of Chicago Census & 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 ensure that the 2020 Census counts are accurate, the US Census Bureau runs programs allowing states, counties, and cities to submit for review data showing their populations may have been enumerated incorrectly or missed. The Population Estimates Program (PEP) releases updated estimates each year following the decennial census. The Post-Census Group Quarters Review challenge program ran in 2023 only. 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 ensure that its population's enumeration 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 met the 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 had been undercounted.

For the Population Estimates challenge program, NORC methodologists evaluated the Census Bureau methodology for estimating the 2022 Chicago population. Using multiple data sources, NORC developed alternative methods to estimate the City’s population and recommended 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 over 5,000 people that had been missed during the 2020 decennial census of group quarters, and almost 7,000 that were missed in the 2021 and 2022 population estimates. Both challenges were accepted by the Census Bureau and will be incorporated into future estimates of the City’s population. Accuracy of population counts and estimates is imperative because the City relies on census data at every level of planning and policymaking. The project is also directly aligned with the City’s efforts to advance equity in how it provides services and resources to residents.

Project Leads

“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.”

Explore NORC Economics Projects

Colorado All-Payer Claims Database

Streamlining the management of Colorado’s health insurance claims


Center for Improving Value in Healthcare (CIVHC)

Research on the Mayors Action Plan (MAP) in NYC

Evaluation results for the Mayor’s Action Plan (MAP) in NYC


New York City Mayor’s Office of Criminal Justice (MOCJ)