Understanding Congressional District Data

INTRODUCTION

IMPLAN provides annual models for U.S. Congressional Districts (CDs). These CD models are constructed as combinations of zip codes and parts of zip codes.  

CONSIDERATIONS FOR ECONOMIC IMPACT ANALYSIS

Substantial redistricting happens after each Decennial Census. Minor changes can occur between Census years and will be published on the Census Bureau’s Relationship Files webpage. IMPLAN incorporates these changes as they occur, and does not produce CD models for data years in which that CD would not have existed (i.e., no retroactive CD incorporation).

This “mapping” between zip codes and CDs only includes zip code tabulation areas (ZCTAs) – it does not include point zip codes. Therefore, IMPLAN uses a variety of sources to determine the CD that each of those point zip codes belongs to; this is done manually when new ones arise. The final mapping of zip codes to CDs thus varies each year, as the list of zip codes varies each year, and can be obtained upon request. 

For details about the zip code data, refer to the articles linked below. 

RELATED ARTICLES

Estimating Congressional District Data

Introduction to Regional Models in IMPLAN

Understanding Zip Code Data

Estimating Zip Code Data

 

Written September 13, 2024