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.