2010 Hawaii Congressional Districts

taransamarth commented 1 year ago

Redistricting requirements

Per Hawaii Revised Statutes 25-2(b)(1)-(4) and (6), as in force for the 2010 cycle, districts must:

1. not unduly favor any person or party;

2. be contiguous, except when encompassing more than one island;

3. be compact;

4. where possible, follow geographical and recognized features and coincide with tract boundaries;

6. where practicable, avoid mixing regions with different socioeconomic interests.

Algorithmic Constraints

We enforce a maximum population deviation of 0.5%. We use Census tracts in line with 25-2(b)(4). In absence of regional knowledge about features and socioeconomic interests, we use municipalities to attempt to enforce 25-2(b)(4) and (6).

Data Sources

Data for Hawaii comes from the ALARM Project's 2010 Redistricting Data Files.

Pre-processing Notes

Islands are manually connected in the adjacency graph, but this has no bearing on the simulation.

Simulation Notes

We sample 5,000 districting plans for Hawaii over 2 independent runs of the SMC algorithm. We use partial SMC to draw one district in the contiguous portion of Honolulu County and assign the remainder to district 2.

Validation

SMC: 5,000 sampled plans of 2 districts on 351 units
`adapt_k_thresh`=0.985 • `seq_alpha`=0.5
`est_label_mult`=1 • `pop_temper`=0

Plan diversity 80% range: 0.13 to 0.61

R-hat values for summary statistics:
     total_vap       plan_dev      comp_edge    comp_polsby      pop_white 
     1.0003967      0.9999217      0.9998505      1.0004449      0.9999415 
     pop_black       pop_hisp       pop_aian      pop_asian       pop_nhpi 
     1.0000249      1.0000658      1.0000407      0.9998316      1.0001422 
     pop_other        pop_two      vap_white      vap_black       vap_hisp 
     0.9998964      0.9999424      1.0000081      1.0001011      1.0001082 
      vap_aian      vap_asian       vap_nhpi      vap_other        vap_two 
     0.9999837      0.9999722      0.9999491      0.9999026      0.9999799 
pre_16_dem_cli pre_16_rep_tru pre_20_dem_bid pre_20_rep_tru uss_16_dem_sch 
     1.0000996      1.0000485      0.9999528      0.9999253      1.0001347 
uss_16_rep_car uss_18_dem_hir uss_18_rep_cur gov_18_dem_ige gov_18_rep_tup 
     1.0000772      1.0000557      1.0000245      1.0000495      1.0001448 
        adv_16         adv_18         adv_20         arv_16         arv_18 
     1.0001370      1.0000480      0.9999528      1.0000489      1.0000567 
        arv_20    muni_splits            ndv            nrv        ndshare 
     0.9999253      1.0000023      1.0000488      0.9999977      1.0001509 
         e_dvs           egap 
     1.0001776      1.0002147 

Sampling diagnostics for SMC run 1 of 2 (2,500 samples)
         Eff. samples (%) Acc. rate Log wgt. sd  Max. unique Est. k 
Split 1     2,469 (98.8%)      7.1%        0.23 1,549 ( 98%)      5 
Resample    2,383 (95.3%)       NA%        0.23 1,557 ( 99%)     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     2,467 (98.7%)      5.7%        0.23 1,597 (101%)      6 
Resample    2,379 (95.1%)       NA%        0.23 1,577 (100%)     NA 

•  Watch out for low effective samples, very low acceptance rates (less than 1%), large
std. devs. of the log weights (more than 3 or so), and low numbers of unique plans.
R-hat values for summary statistics should be between 1 and 1.05.

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

@tylersimko

taransamarth commented 1 year ago

It's hard to see, but there's a singular ring around the entirety of O'ahu such that it generally encircles the Honolulu-centered district -- I'm pretty sure it's water, but I can't actually figure out which tract it is to make sure. Below is from the Honolulu submap with the 2010 enacted plan.

tylersimko commented 1 year ago

@taransamarth This looks good! Thanks for pointing out the geography question. Could you try plotting with geom_sf_label() to take a look at the GEOID of that ring area? It looks like water (and hopefully 0 population), but good to be safe.

taransamarth commented 1 year ago

Yep, looks like it has no population! (filtered the map down to all tracts with pop == 0 and that ring is clearly there)

alarm-redist / fifty-states