Re-run 2020 Rhode Island Congressional Districts

[mzwu]

Redistricting requirements

In Rhode Island, according to the Rhode Island Laws, Chapter 100, Section 2 districts must:

1. be contiguous
2. have equal populations
3. be geographically compact
4. preserve state senate district boundaries as much as possible

Interpretation of requirements

We enforce a maximum population deviation of 0.5%. We add a VRA constraint targeting one minority opportunity district.

Data Sources

Data for Rhode Island comes from the ALARM Project's 2020 Redistricting Data Files. Data for the 2022 Rhode Island enacted congressional map comes from the American Redistricting Project.

Pre-processing Notes

No manual pre-processing decisions were necessary.

Simulation Notes

We sample 5,000 districting plans for Rhode Island across two independent runs of the SMC algorithm. We assigned state senate districts to act like counties so that the simulations minimize the number of senate district splits.

Validation

SMC: 5,000 sampled plans of 2 districts on 423 units
`adapt_k_thresh`=0.985 • `seq_alpha`=0.5
`est_label_mult`=1 • `pop_temper`=0

Plan diversity 80% range: 0.20 to 0.68

R-hat values for summary statistics:
   pop_overlap      total_vap       plan_dev      comp_edge    comp_polsby       pop_hisp      pop_white 
     1.0011601      0.9998474      1.0001080      1.0008089      1.0010635      1.0004997      1.0010977 
     pop_black       pop_aian      pop_asian       pop_nhpi      pop_other        pop_two       vap_hisp 
     1.0016867      0.9998148      1.0005707      1.0000226      1.0007947      1.0011098      1.0004856 
     vap_white      vap_black       vap_aian      vap_asian       vap_nhpi      vap_other        vap_two 
     1.0011033      1.0014459      0.9998114      1.0001400      0.9998713      1.0008779      1.0008341 
pre_16_dem_cli pre_16_rep_tru uss_18_dem_whi uss_18_rep_fla gov_18_dem_rai gov_18_rep_fun atg_18_dem_ner 
     1.0023953      1.0003506      1.0012524      1.0004429      1.0022554      1.0004401      0.9998080 
sos_18_dem_gor sos_18_rep_cor pre_20_dem_bid pre_20_rep_tru uss_20_dem_ree uss_20_rep_wat         arv_16 
     1.0008093      1.0007053      1.0006883      1.0003622      1.0001583      1.0004581      1.0003506 
        adv_16         arv_18         adv_18         arv_20         adv_20  county_splits    muni_splits 
     1.0023953      1.0005364      1.0012370      1.0004125      1.0010571      1.0007327      1.0002114 
           ndv            nrv        ndshare          e_dvs          e_dem           egap 
     1.0010500      1.0003503      0.9999861      0.9999765      1.0005440      1.0027316 

Sampling diagnostics for SMC run 1 of 2
         Eff. samples (%) Acc. rate Log wgt. sd  Max. unique Est. k 
Split 1     2,393 (95.7%)      6.1%        0.33 1,596 (101%)      6 
Resample    2,090 (83.6%)       NA%        0.40 1,494 ( 95%)     NA 

Sampling diagnostics for SMC run 2 of 2
         Eff. samples (%) Acc. rate Log wgt. sd  Max. unique Est. k 
Split 1     2,387 (95.5%)      6.2%        0.34 1,575 (100%)      6 
Resample    2,070 (82.8%)       NA%        0.41 1,496 ( 95%)     NA

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

Additional Notes

Validation plot for number of state senate district splits.

@CoryMcCartan