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2020 Census: Bureau Needs to Ensure Transparency over Data Quality, Finalize Plans for Data Protection, and Examine Lessons Learned

GAO-21-462T Published: Mar 23, 2021. Publicly Released: Mar 23, 2021.
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Fast Facts

We testified about the unprecedented challenges the Census Bureau faced in the 2020 Census, and its efforts to assess data quality, protect privacy, and more.

In response to the COVID-19 pandemic and executive branch decisions, the Bureau shortened the data collection period and made other changes. This introduced risks to the quality of data used for apportionment and redistricting.

The Bureau continues to work on assessing data quality. Looking toward the 2030 Census, it is critical that the Bureau learn as much as possible about the effects of design and schedule changes—such as those made in 2020—on data collection.

A Census worker walking to the front door of a house.

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What GAO Found

The U.S. Census Bureau (Bureau) has critical work remaining to deliver apportionment counts and redistricting data. Specifically, the Bureau did not meet the deadline of delivering apportionment data to the President and announced it would complete the apportionment count on April 30, 2021, because of delays and re-plans in the data collection schedule and changes to the data processing schedule, among other things. COVID-19, executive actions, and uncertainty about the outcomes of ongoing litigation have been contributing factors leading to the delays in delivering apportionment and districting data. As of mid-March 2021, the Bureau was working to complete the remaining processing steps needed to produce the apportionment count, including establishing the final universe of addresses, enumeration statuses, and population count. Regarding redistricting data, the Bureau reported that it is planning to deliver redistricting data to all states by September 30, 2021. Continued focus on the steps needed to complete the apportionment and redistricting files is essential to meeting rescheduled dates.

The Bureau is facing two challenges in completing the count: it has not yet assessed concerns about data quality or finalized plans to protect data.

GAO has previously noted that late design changes increase risk for a quality census. The Bureau is examining ways to share quality indicators of the census in the near term and is considering how to respond to recommendations made by advisory groups related to, among other things, documenting the quality of the population counts that it provides to the President and the Congress. In December 2020, GAO highlighted key quality indicators that the Bureau should consider providing when it releases the apportionment counts; these quality indicators are consistent with the work of the American Statistical Association and the Census Scientific Advisory Committee. Transparency over what is known and not yet known about census quality would help to increase public and congressional confidence in the quality and completeness of the census.

As GAO reported in December 2020, the Bureau's original plans and schedules to protect the privacy of respondent data were impacted by the changes to schedules as a result of COVID-19. In February 2021, the Bureau updated its schedule for near-term activities aimed at protecting respondent data in its redistricting data product. However, as of March 2021, the Bureau had not finalized plans related to the protection of respondent data in products expected to be issued after redistricting.

Looking toward the future, it is critical for the Bureau to ensure that it can learn as much as possible about the effects of the design and schedule changes on data collection and quality control operations. The Bureau is updating plans to assess data collection operations and identify resulting lessons learned from the 2020 Census. Actions taken by the Bureau out of necessity to meet compressed deadlines may be considered as options in future censuses. As part of its planning for the 2030 census, it will be important for the Bureau to assess the impact of the 2020 late design changes and the operations' challenges that arose.

Why GAO Did This Study

The Bureau is responsible for conducting a complete and accurate decennial census of the U.S. population. The decennial census is mandated by the Constitution and provides vital data for the nation. For the 2020 Census, the Bureau was required by law to count the population and deliver the counts to the President by December 31, 2020, in order to determine the number of congressional seats apportioned to each state. The Bureau was also required to deliver population counts for redistricting purposes to the states by March 31, 2021.

In response to the COVID-19 pandemic, the Bureau had to make a series of changes to the design and time frames of the census.

GAO was asked to testify about (1) the status of the 2020 Census, (2) ongoing challenges the Bureau faces in completing the count, and (3) lessons learned to inform planning for the next census. To do so, GAO summarized its prior work assessing the operations of the 2020 Census and identifying lessons learned as planning begins for the 2030 decennial census. GAO also included information from its ongoing work examining the Bureau's progress in developing schedules and plans to protect respondent data.


GAO has previously made recommendations aimed at addressing census data quality concerns and using lessons learned from the 2020 Census to inform planning for 2030. The Department of Commerce has agreed with GAO's findings and recommendations.

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