Detailed DHC-A

The Census Bureau has pushed back the release of the Detailed Demographic and Housing Characteristics File A (Detailed DHC-A) from August to September. The Detailed DHC-A provides population counts and sex-by-age statistics for approximately 370 detailed racial and ethnic groups, as well as about 1,200 detailed American Indian and Alaska Native tribal and village population groups.

The Census Bureau delayed the release to address an inconsistency in the data for certain geographies related to confidentiality protections. To protect respondent confidentiality, the Census Bureau adds “statistical noise” — small, random additions or subtractions — to the data. Previously, these protections could have resulted in different counts for geographies that are treated as multiple levels of geography. For example, the District of Columbia is treated as a state, county and place in the tables and could have received different counts for each level. The Census Bureau is fixing this inconsistency so that these geographies receive the same count regardless of the geographic level.  

The Census Bureau is reviewing public feedback on a Proof of Concept for the Detailed DHC-A. The Census Bureau does not anticipate any additional changes to the release date for the Detailed DHC-A but will keep the public informed.

Public Use Microdata

The Census Bureau also announced plans for public release of 2020 Census privacy-protected microdata, which enable data users to generate custom tabulations for subjects or geographies not included in the published tables. The Census Bureau will release Privacy-Protected Microdata Files (PPMFs) from the production run of the DHC, which incorporates all data included in the 2020 Census Redistricting Data (P.L. 94-171) Summary File. The PPMFs will consist of separate files for people and housing units.

Historically, the Census Bureau released a sample of records, called a Public Use Microdata Sample (PUMS). The Census Bureau is taking a new approach to better protect respondent privacy. While the data in the PPMFs may look like individuals’ actual census records, all data are privacy-protected. They do not include any confidential census responses. Instead, the disclosure avoidance system ensures respondent privacy by applying differentially private statistical noise.

With this approach, the 2020 Census PPMFs can provide the complete set of privacy-protected records for people and housing units. By contrast, the 2010 Census PUMS provided a 10% sample of the full census population, including records for approximately 30 million people and over 13 million housing units. As a result, the 2010 Census PUMS was impacted by sampling error in addition to error from the 2010 disclosure avoidance mechanisms (e.g., swapping, geographic aggregation, category collapsing, data synthesis and top/bottom-coding). The 100% coverage of the 2020 PPMFs means that analyses of the 2020 files will only have to account for the controlled, limited uncertainty introduced by disclosure avoidance and not sampling error.

The PPMFs will be released following the DHC release. The Census Bureau is still developing a more specific schedule.

Noisy Measurements Files

Following the same schedule as the 2020 PPMFs, the Census Bureau announced it plans to release a 2020 Census research data product called the Noisy Measurement Files (NMFs) supporting both the Redistricting Data (P.L. 94-171) Summary File and the DHC.

These files will show the redistricting and DHC data after noise has been infused but before post-processing, which corrects certain inconsistencies within and across tables. Researchers and data scientists can use the NMFs to independently process the files, complete analysis and conduct valuable assessments of the confidentiality protections.

Other 2020 Census Data Products

In May, the Census Bureau plans to announce schedule information for the Detailed Demographic and Housing Characteristics File B (Detailed DHC-B) and Supplemental Demographic and Housing Characteristics File (S-DHC). In refining these schedules, the Census Bureau continues to develop and test the disclosure avoidance algorithms that protect the underlying response data in these data products.

The Congressional District Summary Files are on schedule for release in August. This product retabulates selected summary levels from the DHC for the 118th Congress and 2022 state legislative districts.

More information about these stateside and Puerto Rico data products is available on the About 2020 Census Data Products webpage. The Census Bureau will provide an update on the 2020 Island Areas Censuses data products in the coming weeks.

No news release associated with this product. Tip sheet only.

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