Today’s Privacy-Protected Microdata Files (PPMFs) release reflect a number of Disclosure Avoidance System (DAS) improvements developed over the last few months to reduce distortions caused by post-processing and to improve the accuracy of population counts for legal and political entities. One of the most notable system improvements reflected in the new PPMFs is a change in how the DAS processes data for American Indian and Alaska Native (AIAN) tribal areas. Previously, the DAS performed all of the post-processing along the standard geographic hierarchy. This prior approach led to notable problems for key “off-spine” geographies like the AIAN tribal areas. The new PPMFs reflect system design changes to address this issue. We have implemented a new geographic hierarchy specifically for AIAN tribal areas within each state, and have added a new state-level population invariant for AIAN tribal areas.

The Census Bureau’s recent operational schedule changes have necessitated that we focus all of our current attentions on preparing for the production of the PL94-171 redistricting data files by the statutory deadline of March 31, 2021. Consequently, these new PPMFs are limited to the data necessary to support tabulation of tables P1-P5 and H1 of the redistricting data. Data elements necessary to support other data product tabulations are not included in this release. The full set of data elements necessary to support the Demographic Profiles and Demographic and Housing Characteristics files will be reincorporated into DAS runs at a future date.