2010 Connecticut Congressional Districts

Redistricting requirements

In Connecticut, there are no state law requirements for congressional districts. The Supreme Court of Connecticut set out the following guidelines in the order appointing a special master.

Districts shall be as equal in population as is practicable.
Districts shall be made of contiguous territory.
Districts shall comply with 42 U.S.C. § 1973(b) and with other applicable provisions of the Voting Rights Act and federal law.
Districts shall not be substantially less compact than the existing congressional districts.
Districts shall not substantially violate town lines more than the existing congressional districts.
Districts shall not consider either the residency of incumbents or potential candidates or other political data, such as party registration statistics or election returns.

Interpretation of requirements

We enforce a maximum population deviation of 0.5%, which is in line with the low population deviation observed in the 2000 congressional district plan. We use a pseudo-county constraint described below which attempts to mimic the norms in Connecticut of generally preserving county and municipal boundaries.

Data Sources

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

Pre-processing Notes

No manual pre-processing decisions were necessary.

Simulation Notes

We sample 5,000 districting plans for Connecticut across two independent runs of the SMC algorithm. We use a pseudo-county constraint to limit county and municipality splits. Municipality lines are used in Fairfield County, Hartford County, and New Haven County, which are all counties with populations larger than 40% the target population for a district. No special techniques were needed to produce the sample.

Validation

validation_20221103_1549

SMC: 5,000 sampled plans of 5 districts on 770 units
`adapt_k_thresh`=0.985 • `seq_alpha`=0.5
`est_label_mult`=1 • `pop_temper`=0
ℹ Preparing CT shapefile
Plan diversity 80% range: 0.48 to 0.84
ℹ Preparing CT shapefile
R-hat values for summary statistics:
   pop_overlap      total_vap       plan_dev      comp_edge    comp_polsby      pop_white      pop_black 
      1.008475       1.003795       1.000568       1.008529       1.015606       1.005969       1.003846 
      pop_hisp       pop_aian      pop_asian       pop_nhpi      pop_other        pop_two      vap_white 
      1.003611       1.001044       1.024221       1.006114       1.011754       1.010572       1.006281 
     vap_black       vap_hisp       vap_aian      vap_asian       vap_nhpi      vap_other        vap_two 
      1.004182       1.003960       1.000248       1.019696       1.007332       1.011386       1.018464 
pre_16_dem_cli pre_16_rep_tru pre_20_dem_bid pre_20_rep_tru uss_16_dem_blu uss_16_rep_car uss_18_dem_mur 
      1.005625       1.013105       1.004683       1.012419       1.007100       1.010565       1.008109 
uss_18_rep_cor gov_18_dem_lam gov_18_rep_ste atg_18_dem_ton atg_18_rep_hat sos_18_dem_mer sos_18_rep_cha 
      1.013457       1.011316       1.013450       1.009557       1.014482       1.008501       1.014044 
        adv_16         adv_18         adv_20         arv_16         arv_18         arv_20  county_splits 
      1.005647       1.007237       1.004683       1.012676       1.013380       1.012419       1.010670 
   muni_splits            ndv            nrv        ndshare          e_dvs         pr_dem          e_dem 
      1.001646       1.009415       1.013244       1.008367       1.008485       1.000501       1.011296 
         pbias           egap 
      1.005829       1.013071 

Sampling diagnostics for SMC run 1 of 2 (2,500 samples)
         Eff. samples (%) Acc. rate Log wgt. sd  Max. unique Est. k 
Split 1     2,437 (97.5%)     10.1%        0.33 1,584 (100%)      5 
Split 2     2,367 (94.7%)     11.3%        0.39 1,524 ( 96%)      3 
Split 3     2,325 (93.0%)     10.9%        0.49 1,465 ( 93%)      2 
Split 4     2,238 (89.5%)      3.3%        0.59 1,234 ( 78%)      2 
Resample    1,489 (59.6%)       NA%        0.59 1,844 (117%)     NA 

Sampling diagnostics for SMC run 2 of 2 (2,500 samples)
         Eff. samples (%) Acc. rate Log wgt. sd  Max. unique Est. k 
Split 1     2,439 (97.6%)     10.2%        0.32 1,615 (102%)      5 
Split 2     2,376 (95.1%)      8.2%        0.37 1,527 ( 97%)      4 
Split 3     2,344 (93.8%)      7.3%        0.46 1,461 ( 92%)      3 
Split 4     2,335 (93.4%)      3.2%        0.50 1,298 ( 82%)      2 
Resample    1,839 (73.6%)       NA%        0.49 1,985 (126%)     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

Note: Minor correction to Maine 2020 documentation bundled in.

@CoryMcCartan

alarm-redist / fifty-states