Map Goes Back to the Future for Fairer Redistricting
by Don Leake
Here’s a thought experiment. Imagine you have been miraculously sent back in time to the year 2010. The census numbers for Wisconsin have just been released. With your knowledge of election results from 2012 – 2018, how could you construct a redistricting map that is much more equitable than the extremely gerrymandered one that was adopted?
Someone named Ewan, among others, performed this very experiment and posted the result on DRA 2020, a free web app for creating, analyzing, and sharing redistricting maps. Here it is in reduced form (left), but you can see it up close and personal by going to
https://davesredistricting.org/maps#viewmap::d15deaa8-2e00-4a34-bdcc-1ba860412513
Ewan’s 2010 Assembly District Map
Wisconsin’s 2021 Assembly District Map
For comparison the current assembly district map has been placed on the right. It can be viewed in more detail at
https://davesredistricting.org/maps#viewmap::a355b8c9-3876-46ac-95f6-02fe5cff742c
Both of these maps meet the basic requirements of a traditional state legislative map. The 99 districts have roughly equal populations (within 5% of the ideal population – 57,444 in 2010), every ward is assigned to a district, and there are no districts completely embedded in another. In Ewan’s map, however, all of the districts are contiguous (all wards within a district are connected) while the current state map has a few districts that are not. Judged from these criteria, most people would say that one map is about as good as the other.
In the past decade there has been an increased interest in developing quantitative measures for maps which portray traits that most people would find admirable in any redistricting map. All other things being equal, a map that minimizes the splitting of counties, municipalities, and other communities of interest over two or more districts is preferred. Likewise, districts that are more compact are favored. Every redistricting map must conform to the 1965 Voting Rights Act. Even so, map analysts have developed additional measures that attempt to assess minority opportunity of representation. Finally, the degree to which maps minimize partisan bias is the focus of many measures including, proportionality (how well the percentage of those elected to the Assembly from a political party reflects voting percentage in statewide elections) and competitiveness (the percentage of close district races).
The web app DRA 2020 provides five basic ratings derived from quantitative analysis for every redistricting map drawn using it: county splitting, compactness, minority opportunity, competitiveness, and proportionality. It would take another extensive article to discuss the derivation of each of these ratings. The DRA 2020 website does its best to explain their ratings to the layman. Visit
https://medium.com/dra-2020/analytics-59248d799ea8
to begin a quest for better understanding. It should be noted that all of the ratings are normalized to fall between 0 and 100. Also, bigger ratings are better.
How does Ewan’s redistricting map stack up against the legislature approved one? The radial graph below summarizes the comparison of the ratings. The ratings for the approved map are given on the graph. The ratings for Ewan’s map are: proportionality (76), competitiveness (30), minority opportunity (61), compactness (56), and splitting (78). It doesn’t take a genius to see which map is better based on these criteria. The orange pentagon associated with Ewan’s map completely encloses the green one representing the current district map.
The DRA 2020 analytics show that the legislature could have done a much better job constructing and approving a fair map in 2011. There is no reason for the county splitting rating to be so low. This is a characteristic solely dependent on the design of the map. The lower proportionality rating would only be established by elections after 2011. However, this result was predictable given that the map was developed in secret with the intent of Republican bias.
Even though Ewan’s map (the state’s map too) has become obsolete as the population of Wisconsin has grown and redistributed itself over the last decade, it does teach us a valuable lesson. Thoughtful consideration in making district maps fairer instead of more biased is possible. How can we encourage this? One way is to draw maps that challenge the maps proposed by the legislature to meet reasonable standards. This is the mission of The People’s Map Commission (PMC). If the legislature’s maps can meet these standards, then it should be approved. If not, the courts will decide which maps to adopt.
Do we need to wait until 2020 census numbers become available in September to start drawing maps? The answer is a resounding NO. The Census Bureau’s American Community Survey (ACS) from 2019 provides a good estimate of Wisconsin’s population distribution for that year. DRA 2020 conveniently provides the option of using this data in its software. Anyone who is willing can learn the easy-to-use tool through the articles and videos provided by the website.
https://davesredistricting.org/maps#home
A handful of Wisconsin Assembly maps using 2019 ACS data have already been published on the DRA 2020 website (register to see them). Hopefully, when the 2020 census data arrives, these maps will require minimal adjustment. To avoid the potential bias of data from a single election, these maps used composite election data from 2012-2018 just as Ewan did. Maps may be submitted to the PMC through this link.
https://govstatus.egov.com/peoplesmaps/contact-commission
Even though the PMC is charged with drawing its own maps, it is currently soliciting maps drawn with any web tool, as well as hand-drawn ones. Perhaps they will find your map compelling. While you are at it, submit your Assembly map to the PierceCountyGRO contest
https://piercecountygro.org/mapcontest
You may find yourself $599 richer for doing so. Let the best map win!