Please note. Throughout this memo partisan baselines for each district are calculated as the average of the 2020 presidential, 2018 gubernatorial, and 2016 presidential elections. Seats “won” by either party are calculated by applying a uniform swing to this partisan baseline. This does not take into account incumbency effects.

Partisan lean of proposed plans

I define a “competitive” seat as one with a partisan baseline of 5 points or less. In other words, neither party typically receives more than 52.5% of the 2-party vote. By this definition, the current maps contain 9 competitive Assembly seats. The WI Legislature’s plan would reduce this to 7. Common Sense Wisconsin would raise it to 11. The People’s Map Commission would create 14.

Partisan lean of seats in proposed maps
Democratic Republican
0-5 D 5-10 D Safe D 0-5 R 5-10 R Safe R
People's Map Commission 6 8 30 8 5 42
Common Sense Wisconsin 3 7 29 8 6 46
WI 2011 4 5 29 5 7 49
WI Legislature 2 2 32 5 5 53

Seats by swing

This graph shows the number of Assembly seats won by Democrats depending on the statewide vote swing. By far the best map for Democrats is that proposed by the People’s Map Commission. Under this plan, Democrats could expect to win 44 seats in a statewide tie. To win a majority (50 seats), they would need to win the state by about 3.6 points (i.e. 51.8% of the 2-party vote).

The plan proposed by the Wisconsin Legislature is substantially worse than even the existing plan. If that plan were enacted, Democrats would likely win 36 seats in a statewide tie. They would need to win the state by 12.4 points in order to carry a majority of seats (i.e. 56.2%).

 

Democratic electoral performance across selected district plans
seats in statewide tie minimum swing for majority
Common Sense Wisconsin 38 7.5
People's Map Commission 44 3.6
WI 2011 37 8.6
WI Legislature 36 12.4

 

District changes

The map below shows how districts would change under each scheme. Each pin shows the residence of the current incumbent. Toggle between different baselayers to see how the districts would change.

Where possible, addresses were taken from the “voting address” listed on each legislator’s official profile. When this was unavailable, I used the address listed on the incumbent’s most recent election filing. It is possible, even likely, that some legislators have moved since then.

Please note. I believe Scott Allen (R-97) has likely moved. He does not list a full address on his legislator profile, but he does list a zip code (53188) which differs from the zip code of his address in 2020 (53189). This makes sense, because his 2020 address would place him ever-so-slightly in a district with 2 other Republican legislators under the Republican legislature’s plan. In reality, I expect his new address is in the Republican legislature’s redrawn District 97, which otherwise contains no resident incumbent.

Consequences for incumbents

Please note. All these calculations are based on the most recent address I could find for each incumbents. Some incumbents may have moved, making these results outdated.

As the map suggests, the People’s Map Commission makes the most dramatic changes to the existing map, whereas the WI Legislature’s proposal mostly makes small tweaks. Eight-two percent of the population would remain represented by their old incumbent under the Legislature’s map. Fewer, 67%, would be represented by the same incumbent under the Commission’s proposal.

 

Total population with the same incumbent
population
total voting age
Common Sense Wisconsin 67.4% 67.4%
People's Map Commission 46.8% 46.8%
WI Legislature 81.9% 81.8%

 

The WI Legislature’s plan clearly prioritizes incumbent protection. Based on the most recent addresses available, 92 current Assembly Representatives would remain the sole incumbent of their new district. Four legislators would find themselves in districts with 2 legislators each, and in one instance 3 legislators would find themselves districted together.

By contrast, the People’s Map Commission would create just 53 districts with 1 resident incumbent and 24 districts with 0 incumbents residing therein. Twenty of the new districts would hold 2 incumbents, while the remaining 2 would hold 3 sitting legislators.

 

Incumbent protection statistics by plan
Districts with this # of incumbents incumbents in multiple incumbent districts
0 1 2 3
Common Sense Wisconsin 11 78 9 1 21
WI Legislature 4 92 2 1 7
People's Map Commission 24 53 20 2 46

 

The graphs below show how each incumbent’s district would change under each plan. The graphs do not show “new” districts created without a resident incumbent.

For each incumbent, the arrow extends from the partisan baseline of their current district to the partisan baseline of the proposed new district in which they would reside if the plan in question was adopted.

WI Legislature’s Plan

People’s Map Commission Plan

Common Sense Wisconsin Plan

Appendix