2020 Illinois Congressional Districts

[kevpwang]

Redistricting requirements

In Illinois, districts must, under Ill. Const. Art. IV, § 3:

1. be contiguous
2. have equal populations
3. be geographically compact

Interpretation of requirements

We enforce a maximum population deviation of 0.5%.

Data Sources

Data for Illinois comes from the ALARM Project's 2020 Redistricting Data Files.

Pre-processing Notes

No manual pre-processing decisions were necessary.

Simulation Notes

We sample 5,000 districting plans for Illinois. To balance county and municipality splits, we create pseudocounties for use in the county constraint, which leads to fewer municipality splits than using a county constraint. These are counties outside of Cook County and DuPage County. Within Cook County and DuPage County, each municipality is its own pseudocounty as well. Cook County and DuPage County were chosen since they are necessarily split by congressional districts. To comply with the federal VRA and to respect communities of interest, we add weak VRA constraints targeting one majority-Black district (IL-01) and one majority-Hispanic district (IL-04).

Validation

Checklist

• [x] I have followed the instructions
• [x] I have updated the tracker
• [x] All TODO lines from the template code have been removed
• [x] I have merged in the master branch and then recalculated summary statistics
• [x] I have run enforce_style() to format my code
• [x] The documentation copied above is up-to-date
• [x] There are no data files in this pull request
• [x] None of the file output paths (for the redist_map and redist_plans objects, and summary statistics) have been edited

@CoryMcCartan

[kevpwang]

[kevpwang]

Thanks—all should be updated now.

[CoryMcCartan]

Awesome, merging in!