April 8, 2022:  We want to alert data users to the discovery of technical issues in the Summary File creation process that converted the privacy-protected microdata into the 2010 Demonstration Data for the Demographic and Housing Characteristics File (DHC) (v. 2022-03-16).

Based on our analysis, these technical issues will impact data users’ ability to create accurate housing file tables for urban areas, state congressional districts, state legislative districts, ZIP Code tabulation areas, and school district geographies from the State Summary Files. Technical errors in the geographic header files will cause a misalignment of data for all state housing summary levels between 420 – State-Urban Area and 970 – State-School District (Unified)/Remainder.

In addition, we identified errors in the person and housing counts provided in the geographic header files for some geographies. The counts in the geographic header files are included as a processing validation check only. Users should rely on the counts provided in the summary files for analysis, and those counts are unaffected by this issue.

We are grateful to Jan Vink of Cornell University who brought these issues to our attention. “Crowd sourcing” data review with the data user community allows us to release -- relatively quickly – multiple, iterative versions of demonstration data. This external review process complements our limited, internal review of the data prior to its release. Please continue to alert us to anomalies via 2020DAS@census.gov.

We are updating the affected files and will notify you once they are re-released. If your analysis does not rely on the summary levels identified above, the Person Summary Files, or the National Summary Files, you can continue to use the unaffected data in the interim.

We will ensure that data users have a full 30-day period to submit feedback.

We apologize for the inconvenience this may cause.