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Community of Interest (COI)

What is a Community of Interest COI?

A community of interest COI is a group of people with shared concerns, interests, and characteristics. Every COI is unique; they might be formed around neighborhoods or the physical landscape, cultures, values, and many other things. Because of these shared interests and concerns, a common redistricting criteria is that COIs be considered during the process.

Does My State Require Consideration of COIs?

A majority – but not all – states require consideration of communities of interest. The exact definition of “consideration” and “community of interest” varies widely, however.

Michigan’s Constitution states:

“Districts shall reflect the state’s diverse population and communities of interest. Communities of interest may include, but shall not be limited to, populations that share cultural or historical characteristics or economic interests. Communities of interest do not include relationships with political parties, incumbents, or political candidates. Communities of interest do not include relationships with political parties, incumbents, or political candidates.”

Arizona’s Constitution, in contrast, is more terse, stating only that:

“[d]istrict boundaries shall respect communities of interest to the extent practicable.”

Please consult your state’s page on All About Redistricting to find out whether COIs must be considered during the legislative or congressional redistricting processes.

How are COI Maps Submitted to Redistricting Bodies?

There are several ways in which communities of interest provide public input. There are many free mapping tools that enable the drawing of COI maps. These maps might be downloaded and submitted in several different file types, such as csv assignment files, geojsons, shapefiles, pdfs, and other formats. In other cases, the COI is described in written testimony, or accompanies a map in some format. These maps might be submitted to a redistricting body directly through an online portal, via email, or by testifying at a public hearing.

Community of Interest Map Collection Project

Collecting and creating a database of COI maps submitted during the 2021 redistricting cycle

The Community of Interest COI Map Collection Project aims to collect COI maps submitted to legislative and congressional redistricting bodies and organizations during the 2021 redistricting cycle. Learn More

Watch Trainings

This playlist includes an introduction to COI’s as well as a three-part series that prepares users to analyze whether a proposed or enacted plan considers Communities of Interest (COIs), importing a district plan and Community of Interest map into DistrictBuilder and DRA 2020 and the process of importing a district plan and one or more community of interest maps into QGIS and Python.

What is a Community of Interest (COI)?

How to answer questions about your community

Learn about the kind of data that are used and how you can find insights about your communities of interests using them. This training includes a demonstration on how to use the data that is available for download for free with the Redistricting Data Hub.

Part 1: Preparing to Analyze Communities of Interest Maps

The first training of this three-part series prepares users to analyze whether a proposed or enacted plan considers Communities of Interest (COIs). We show you where to find and download COIs and enacted plans and explain the geographies and file types encountered when working with these maps.

Part 2: Using DistrictBuilder and DRA 2020 to Analyze a Community of Interest with Respect to Proposed Maps

The training walks you through the process of importing a district plan and Community of Interest map into DistrictBuilder and DRA 2020. We provide guidance to prevent common issues or mistakes and review the metrics and analysis capabilities unique to each tool.

Part 3: Using QGIS and Python to Analyze One or More Communities of Interest with Respect to Proposed Maps

The training walks you through the process of importing a district plan and one or more community of interest maps into QGIS and Python. We are pleased to have John Holden, creator of the QGIS Redistricting Plugin, present the QGIS demonstration and answer your questions. In the remainder of the training, we will introduce our publicly available script file that makes it easy to analyze multiple COIs and generate heat maps and metrics of interest. Watch Video

COI Analysis

This program allows a user to import COI maps, such as all those submitted by the public, and returns a map of hot-spots where multiple COI map submissions outlined the same area as a community. This is done by calculating an overlap score for each census block. Each census block receives a higher score as more COI maps include the block in their community. As more people identify a geographic area as a Community of Interest, that area’s overlap score increases; that geographic area then appears darker on the map. A user can also import a shapefile of a state’s current districts at any level (U.S. House, state senate…) and the program will outline the borders of the districts in the plan so that the COI hot-spots can be visualized with respect to the final district borders. Access the script on GitHub

This program works with Community of Interest maps that were created in DavesRedistricting, Districtr, DistrictBuilder and Representable.

Do you have more questions?

Our help desk team can answer your questions about redistricting data and the redistricting process. Send a message and they will respond within one buisness day!