MCDC News and Updates

Geocorr and Other Application Updates (December 2023)

MCDC has a number of significant application updates to announce this month.

We added several new geography types to the Geocorr 2022 application, including the new core-based statistical areas (CBSAs, which include metropolitan and micropolitan statistical areas), metropolitan divisions, and combined statistical areas (CSAs), all of which were released by the Office of Management and Budget in July 2023. We also added the “new” Connecticut planning regions, and updated the urban areas to match those currently used by the Census Bureau.

The Connecticut planning regions pose a special problem for those using Geocorr to do county-level correlations. Earlier this year, the State of Connecticut finalized adoption of the State’s nine Councils of Governments (COGs), also called planning regions, as the county-equivalent geographic unit. Unfortunately for longitudinal county-level data users, the new regions don’t match the boundaries of the state’s eight counties that were previously used for census data tabulation.

In Geocorr, we’ve designated the planning regions as a new geography type that exists only in Connecticut. The unwanted consequence is that if you try to run a correlation using the new planning regions with any state besides CT, you’ll get an error. Thus, if you want to run a county-to-target correlation for many states or the whole nation, you’ll need to run it twice: once with all the states except CT, and then a second run to do the region-to-target correlation just for CT.

For more information about the CT changes, see Final Change to County Equivalents in Connecticut and the Final Federal Register Notice, Change to County Equivalents in the State of Connecticut.

Two other MCDC data applications have also been extensively updated: Population Estimates by Age and Population Trends with Demographics. The earlier versions of these apps relied on the so-called “bridged-race” single-year-of-age data from the National Center for Health Statistics (NCHS). Unfortunately, this very valuable data source was discontinued in 2020. These applications now use the annual population estimates published by the Census Bureau’s Population Estimates Program. Rather than single-year-of-age data, these estimates are aggregated into 18 five-year age “buckets” or cohorts. Therefore, it’s no longer possible to extract single years of age or make custom cohorts with the MCDC apps. Moreover, the census race classifications changed in 2000. Before then, there was not a separate race category for “Hawaiian and other Pacific Islander”. These populations were included in the “Asian” category prior to 2000. In addition, there was no category for “Two or more races” before 2000. Please exercise due caution when using pre-2000 population estimates from our applications and from the Census Bureau sources.

Please contact the MCDC web manager with any questions or comments.

Data Updates (September 2023)

We have a few routine data and application updates to announce this month.

  • On August 24, we posted new a zcta_master set to our geographic reference data collection. Zcta_master is a comprehensive ZCTA (ZIP Code Tabulation Area) resource with geographic correspondences and vintage 2021 ACS-based demographics. This new version uses ZCTAs as defined for the 2020 census. We have our usual SAS dataset, accessible via the Dexter data extraction tool, as well as a CSV file.
  • We found some minor errors in the new DHC data collection. Tract codes were missing final digits. These have been corrected.
  • Two of our workhorse data applications, uex2dex and Dexter, underwent substantial code updates and revisions.
  • Just this week, we published the 2022-vintage round of intercensal population estimates, released earlier this year. These include the CASRH (characteristics of age, sex, race, and Hispanic origin) data for all states, population ranks, housing unit estimates, and the new “curmoests” Excel file (Missouri current population estimates for the state, counties, subcounty units, and cities and towns).

Please contact the MCDC web manager with any questions or comments.

Urban/Rural Categories now available in Geocorr 2022

We’ve added the new urban areas to the Geocorr 2022 application this month.

There are two new options in Geocorr for source or target geographies. Urban areas are the complete areas with Census Bureau codes; for example, the Columbia, MO urban area with UA code 18937. Urban/rural portion uses a binary designation (“U” or “R”) for each block to calculate the fraction of urban and rural population for any other geography.

There are significant changes to the urban/rural classifications for the 2020 Census. One major change is that we no longer have two different types of urban area. Previously, there were urbanized areas and urban clusters (collective called urban areas), but now there are only urban areas of a single type. In addition, the method for defining these areas is much more complex than before. The short version of the new definition, from the Bureau’s Urban and Rural page, is:

For the 2020 Census, an urban area will comprise a densely settled core of census blocks that meet minimum housing unit density and/or population density requirements.  This includes adjacent territory containing non-residential urban land uses.  To qualify as an urban area, the territory identified according to criteria must encompass at least 2,000 housing units or a population of at least 5,000.

Among other factors, the longer definition includes:

  • Initial criteria for blocks: >= 425 dwelling units/ square mile, or substantial impervious surface >= 20%, or group quarters facility and >= 500 population/square mile.
  • Candidate blocks are then assembled into urban areas:
    • Start with an initial contiguous core area with >= 500 dwelling units.
    • Add nearby noncontiguous urban blocks: any number of “hops” <= 0.5 mile over land area, and up to one “jump” of 0.51 – 1.5 miles over land area.
  • Combined urban area must have at least 5,000 population or at least 2,000 housing units.
  • Enclaves or surrounded areas are added (or removed), and additional qualifying criteria (airports, indentations, high-employment areas, impervious areas) are applied.

For a complete list of elements comprising the new definition, refer to the Federal Register Notice. See also this helpful PDF, Differences between the Final 2020 Census Urban Area Criteria and the 2010 Census Urban Area Criteria, for more information about the changes.

Please report any errors to Glenn Rice (

More Geographies Added to Geocorr 2022

New in the Geocorr 2022 application this month:

We’ve added current American Indian / Alaska Native / Native Hawaiian areas. These areas include American Indian reservations (state and federal), off-reservation trust lands, Hawaiian home lands (HHLs), joint-use areas, Oklahoma tribal statistical areas (OTSAs), Alaska native village statistical areas (ANVSAs), state designated tribal statistical areas (SDTSAs), and tribal designated statistical areas (TDSAs). Alaska Native Regional Corporations [ANRCs] and tribal subdivisions are not included in MABLE/Geocorr.

The Bureau released block equivalency files for 118th congressional districts and 2022 state legislative districts this month — two months early! — so we’ve replaced the “provisional” CD/SLDs with these new “official” ones.

The next major addition to Geocorr will be the new urban/rural classifications, expected December 2022 or January 2023. There are significant changes to the urban/rural classifications for the 2020 Census — we’ll post more about that later, but if you’re interested, the Bureau’s Urban and Rural page has more detail.

Please report any errors to Glenn Rice (

Geocorr 2022: Now With 2020 (and 2010) PUMAs

We’ve added several new geography types to the Geocorr 2022 application. The new 2020-vintage PUMAs (public use microsample area), released just a few weeks ago, are now available. By request, we’ve also restored the 2010-vintage PUMAs to facilitate crosswalks.

Because the new PUMAs are based on the 2020 census but were released in 2022, we’re interchangeably calling them 2020 and 2022 PUMAs. (This is the same way we handled the 2010/2012 PUMAs.)

For more information about PUMAs, please refer to our “All about PUMAs” page (now due for a revision!) or the Census Bureau’s PUMA reference.

As usual, please report any errors to Glenn Rice (

Post-Redistricting Geographies Now Available in Geocorr 2022

Geocorr 2022 just got better!

Many of our users have been asking when the new, post-Census-2020 Congressional districts would be available in Geocorr. The short answer is that 118th CDs are now included in Geocorr 2022, along with current state legislative districts.

A somewhat longer answer is that the U.S. Census Bureau has not yet released shapefiles or block lists for building 118th CDs or current SLDLs or SLDUs from 2020 tabulation blocks — and is not planning to do so for several months yet.

The Bureau’s Redistricting Data Office (RDO) intends to publish block equivalency files for the 118th Congress and for the 2022 state legislative districts, but not until December of 2022 at the earliest. And, the Bureau’s Geography division will not be releasing block allocation files for the same areas at all. However, the new areas will be published as shapefiles in the cartographic boundary files collection around April or May of 2023. They may also be released with the 2022 TIGER/Line shapefiles, generally around October.

Because of this lack of availability, we obtained new CD and state legislative boundary shapefiles from The American Redistricting Project, merged them, and ran intersections against 2020 TIGER/Line block shapefiles to determine how every block fits into the new districts. This was a tedious process, especially since the block and district shapefiles didn’t line up exactly, but we now have enough data to use for correlations.

With all that said, the new legislative geographies in Geocorr 2022 should be considered provisional until such time as they can be verified via official Census Bureau block equivalency files or shapefiles.

Of lesser interest (mainly for our Missouri users), Geocorr 2022 now also includes the most recent MO library districts.

As always, please contact Glenn Rice ( with technical questions.

Data Updates (June 2022)

We have a handful of data updates to report this spring.

In addition, for the convenience of our GIS users, we’ve added national shapefiles for the 2022-vintage congressional districts (118th Congress) and state upper- and lower-chamber legislative districts. These were compiled from individual state shapefiles downloaded from the American Redistricting Project. We have attempted to clean and normalize the attribute tables. Please note that these are not official Census Bureau shapefiles.

Please contact the MCDC website manager with any questions or comments.

Geocorr 2022

We’re happy to announce a new version of Geocorr based on 2020 decennial census geographies. Thank you for your patience!

Currently, Geocorr 2022 comprises the following geographies for all states, DC, and PR (where applicable):

  • nation (aka “Entire universe”)
  • states
  • counties
  • minor civil divisions (MCDs; includes townships and other county subdivisions)
  • tracts
  • block groups
  • blocks
  • places (towns, villages, cities, etc.) and census-designated places (CDPs)
  • core-based statistical areas (CBSAs; includes metropolitan and micropolitan statistical areas)
  • upper- and lower-chamber state legislative districts
  • Congressional districts (116th Congress)
  • ZCTAs (ZIP codes)
  • NECTAs and NECTA divisions
  • elementary, secondary, and unified school districts
  • “best” school districts and types
  • county and place size categories
  • hospital service areas and referral regions

In addition, Geocorr 2022 includes the following regions for the state of Missouri only:

  • Regional Planning Commissions
  • University of Missouri Extension regions
  • MO Dept. of Economic Development (MERIC) regions
  • MO Dept. of Transportation districts
  • MO Area Agencies on Aging
  • MO BRFSS regions

We’ll add other geography types as they become available.

Longtime users of the Geocorr applications may notice a few other changes. Geocorr 2022 does not include the concentric ring pseudo-geocode options, nor the bounding box filter option. Our server logs indicated that these options were rarely used, and in a couple of instances were not actually functional. The HTML (web page) report option is now unchecked by default. The report output is the most resource- and time-intensive block of Geocorr’s code, and frequently causes program timeouts when very long reports (e.g., those using blocks) are requested.

Although Geocorr 2022 has been thoroughly tested, it should be considered a “beta” version for the moment. Please report any errors to Glenn Rice (

U.S. Census Bureau “Data Gem” offers a quick look at Geocorr

The U.S. Census Bureau’s Census Academy recently released a short video in its “Data Gems” series providing a brief overview about using MCDC’s Geocorr tool to create geographical correspondences. “Whether you are looking for estimates for the nation or a population count for your city block, geography is a critical element to using and accessing Census data. The State Data Center in Missouri [MCDC] developed a great resource to help us work with Census Bureau’s geographies. In this Data Gem, you will learn how to use the Geocorr to identify the geographies that make up your area.”

The Census Academy is the Bureau’s virtual hub for learning data skills, including visualization, population and housing tools, geography, and other topics. The Data Gems are a series of short “how-to” videos for data users looking to quickly enhance census data knowledge.

Data Updates (Spring 2021)

We’ve updated many of our population-related applications and datasets over the past couple of months.

As always, please contact the MCDC website manager with any questions or comments.