The legislative branch of the US government is composed of Senators, with two from each state, and 436 US House of Representative members, representing areas across the nation referred to as Congressional Districts.
This article will walk you through everything you need to know about using these Congressional Districts in your Economic Impact Analysis.
The Congressional Districts (CD) in IMPLAN are lagged behind the current structure of the House of Representatives. Beginning with the 2019 dataset, the 116th Congressional Districts are utilized. This is the session of Congress that convened between 2019 and 2020.
Congressional Districts are made up of zip codes. Note that the Census Bureau does not use estimates at what we know as zip code boundaries.
Instead, they use: Zip Code Tabulation Areas (ZCTAs). ZCTAs are created by the Census Bureau based on the predominant zip code in a simulated area. Fun fact, the Census calls them ZCTAS (zick-tas).
So, we start by manually creating a correspondence between each ZCTA and CD. When a ZCTA has to be split across more than one CD, it is divided equally, not based on any information about the area. So, if a ZCTA exists in two CDs, it will be split so that each CD gets half of the activity. For more information on how zip codes are tabulated in IMPLAN, check out the article Estimating Zip Code Data. The main thing to note is that since zip codes appear and disappear every year, IMPLAN creates a new bridge between Zip Codes and CDs every year. When a new CD is added by Congress, we incorporate that new CD into the dataset. You can find the crosswalk between zip codes and CDs in the article 546 Industries, Conversions, Bridges, & Construction - 2019 Data.
FINDING THEM IN IMPLAN
Congressional Districts are easy to find in IMPLAN. Head to your Regions screen and simply begin typing the state abbreviation. To look at the CD where IMPLAN HQ is located, start typing in “NC” and then the drop down list will populate. Typing in “NC-12” will specifically show North Carolina Twelfth Congressional District. Note, the 33 CDs in Puerto Rico are not in IMPLAN.
Written June 21, 2021