Census Data Release Timeline

Census and Data Equity Resources 09.16,21

A PDF version of this fact sheet is available here.

August 12

  • The Census Bureau will provide redistricting data in legacy file format – the file format they have provided in previous decades. These legacy format files will include:
    • A geographic header (geoheader) file that contains geographic information
    • Three separate data segments per state with data tables, including:
      • Housing unit counts and occupancy status
      • Population totals
      • Population totals by race and Hispanic/Latino origin
      • Voting age population by race and Hispanic/Latino origin
      • Group Quarters population by major Group Quarters type
    • The Census Bureau will provide the additional items to help states, localities, and other data users access and utilize the data,[1] as this is not an “easy-to-use” format.
    • Demonstration data in the form of Privacy-Protected Microdata Files (PPMF) that will show the effects of the actual 2020 Census differential privacy application (a Disclosure Avoidance System method) on 2010 Census data.
    • Three new diversity measurements down to the county level for 2010 and 2020 (to facilitate comparisons):
      • The Diversity Index will indicate the probability that two people chosen at random will be from different race and ethnic groups.
      • Prevalence rankings, which will show the most common group in an area, down to the third largest group.
      • Prevalence maps, which will show the geographic distribution of the largest or second-largest race or ethnic group.

August 18

  • Release of summary operational metrics: summary county- and tract-level metrics by state for selected previously released operational quality metrics.

August 25

  • Release of item nonresponse rates for population count, age or date of birth, race and Hispanic origin questions. These rates will be available at the national and state level, as well as for the District of Columbia and Puerto Rico.

Mid-September

  • American Statistical Association (ASA) state-level operational metrics report.

September 16

  • Census Bureau will formally transmit the P.L. 94-171, or redistricting, files to governors (or highest elected officials) and legislative leaders of each state and Tribal government, the District of Columbia, and Puerto Rico.
  • The Census Bureau will provide the same redistricting data that it provides in August, but in two additional, easier to use formats:
  • A toolkit in the form of DVDs and flash drives to the state officers (or their designees) and to any other public bodies responsible for their state’s legislative apportionment or districting.
    • This tool will include an integrated software browsing tool and an extraction menu that allows for easy extraction of large datasets.
  • States and the public will also have access to the data on census.gov.
  • The bureau will also provide the TopDown Algorithm production code base (the code used for disclosure avoidance for redistricting data) for P.L. 94-171 redistricting summary datafiles, related technical papers, and an “Introduction to Differential Privacy” handbook.

[1]These items include:

  • Prototype data –> used to build and test systems in advance of the official data release so that states can begin work immediately when they receive the 2020 data.
  • Microsoft Access database shell –> comes with a step-by-step guide on how to use it to import the redistricting data and extract data from the files.
  • A list of frequently used summary level codes –> users can check this list to look up the summary level code that corresponds to some of the most commonly used types of geography. All data are available at various geography types, including states, counties, places, congressional or legislative districts, voting districts, census tracts, and blocks.
  • SAS import scripts –> help users import the data files into the SAS statistical software.
  • R import scripts –> help users import the data into the R statistical software.
  • Geographic support products –> including shapefiles for the new 2020 Census blocks, updated boundaries for legal governments, and other geographic information.