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2020 Census Population Counts for Apportionment are Now Available

The Census Bureau is building and evaluating the new cryptography-inspired disclosure avoidance system (DAS) for the 2020 Census through a series of development “sprints.” To help you assess iterative DAS design progress, we apply DAS updates to 2010 Census data after significant sprints so you can compare differences as follows:

  • Detailed Summary Metrics allow you to measure iterative design progress after significant sprint cycles. Your input and that of the larger data user community helped shape these metrics, which continue to evolve.
  • Privacy-Protected Microdata Files (PPMFs) are the underlying, untabulated microdata files for the entire nation used to generate the Detailed Summary Metrics.
  • Privacy-Protected Summary Files (PPSFs) are the PPMFs in a user-friendly tabulated and formatted summary form. We are grateful to the University of Minnesota’s IPUMS National Historical Geographic Information System (NHGIS), members of the Committee on National Statistics’ (CNSTAT) expert group, who have volunteered to produce these files. This partnership allows a faster turnaround than would otherwise have been possible in-house, and enables Census Bureau staff to continue their focus on other important data collection and processing work.

These tools are a direct response to your requests for more flexible DAS evaluation tools.

Note that these files are privacy protected. While the data in the PPMFs look like individual records, all of the data is privacy-protected. The microdata records generated by the DAS ensure respondent privacy through the application of differentially private statistical noise. The microdata included in the PPMF do not include any individual’s actual census responses. They are simply the microdata format used by the Census Bureau’s production system to produce privacy-protected tables that the DAS generated.

DAS Demonstration Data and Progress Metrics Updates​

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There are two sets of Privacy-Protected Microdata Files (PPMFs), record layouts, and Detailed Summary Metrics in this release:

  • One set with a global privacy-loss budget ("epsilon") of 12.2 (10.3 for persons and 1.9 for housing units, approximating the anticipated final PLB level).  In the FTP directory, those files include “12-2” in the file names (e.g, ppmf_20210428_eps12-2_P.csv and ppmf_20210428_eps12-2_U.csv).
  • A second set with the global-privacy loss budget ("epsilon") of 4.5 (4.0 for persons and 0.5 for housing units, as used for prior demonstration data). In the FTP directory, those files include “4-5” in the file names (e.g, ppmf_20210428_eps4-5_P.csv and ppmf_20210428_eps4-5_U.csv).

We encourage data users to closely analyze this demonstration data. Feedback received by May 28, 2021, will be considered. Email feedback to: 2020DAS@census.gov; include “April PPMF” in the subject line.

Particularly useful feedback would describe:

  • Fitness-for-use: Based on your analysis, would the data needed for your applications (redistricting, Voting Rights Act analysis, estimates, projections, funding data sets, etc.) be satisfactory?
    • How did you come to that conclusion?
    • If your analysis found the data to be unsatisfactory, how incrementally would accuracy need to change to improve the use of the data for your required or programmatic use case(s)?
    • Have you identified any improbable results in the data that would be helpful for us to understand?"
  • Privacy: Do the proposed products present any confidentiality concerns that we should address in the DAS?
  • Improvements: Are there improvements you’ve identified that you want to make sure we retain in the final design? Be specific about the geography and error metric for the proposed improvement.

We will provide additional metrics and educational webinars throughout the month of May to help you with that analysis. (Subscribe to our newsletter for the release and other updates.)

Committee on National Statistics (CNSTAT) Expert Meeting Presentations

Presentations from the ongoing expert panel meetings convened by the Committee on National Statistics regarding DAS development:

2020 Census Data Products Crosswalk

This document provides the proposed tables that will be included in the Public Law 94-171, Demographic Profiles (DP), and the Demographic and Housing Characteristic File (DHC). Additionally, tables are included for the 2010 Demonstration Data Products.

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Share Your Thoughts

We appreciate your engagement and encourage you to email comments and suggestions to 2020DAS@census.gov.

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