Wisconsin Legislative Redistricting

[jimrtex]

jimrtex, confirming that you have not finished all of the Districts in Dane County, correct?

That is correct. Until I do the Madison districts, I might change the suburban districts.

[jimrtex]

16 counties form five districts in Northern Wisconsin



30. Marinette 0.727; Forest 0.162; and Florence 0.77. 0.962

(I skipped a district number, which I assigned to this district when I found it.

83. Oneida 0.627; Langlade 0.348; and Menominee 0.74. 1.048

84. Douglas 0.769; and Burnett 0.269. 1.038

87. Vilas 0.373; Ashland 0.281; Bayfield 0.261; and Iron 0.103. 1.019.

97. Sawyer 0.288; Washburn 0.277; Rusk 0.257; and Price 0.246.  1.068.

(If required to get AD-97 below 1.050, Round Lake and Spider Lake towns will be transferred from AD-97 to AD-87).

[jimrtex]

Wood (1.301) and Clark (0.604) collectively have a population equivalent to 1.905 districts and will have two districts. One district will be wholly in Wood, while the other will be about 2/3 in Clark, with the remainder in Wood. Because the overall deviation is -4.7%, particular attention will be paid to balanced division.



Wood County detail.



Including Marshfield with the Clark-dominated district is sufficient, leaving the Wood based district concentrated in the Wisconsin Rapids area in  the southeastern part of the county.

85. Wood: (all but portion in AD-86) 0.948. 0.948

86. Clark (all) 0.604; Wood: Cameron town, Lincoln town, and Marshfield city 0.353. 0.956

[jimrtex]

Monroe 0.778, Juneau 0.464, Adams 0.363, and Jackson 0.356 have a population equivalent to 1.961 districts, and will have two districts. This will require a split of Monroe.

One district will be comprised of 80% of Monroe and Jackson. Monroe will have almost 2/3 of the district population. The other district will include Juneau, Adams, and the remainder of Monroe.



Monroe detail.



The split places the two largest towns of Sparta and Tomah in the Monroe-dominated district, with rural towns along the eastern edge placed in the district with Juneau and Adams.

88. Jackson (all) 0.356; and Monroe: Adrian town, Angelo town, Cashton village, Grant town, Greenfield town, Jefferson town, La Grange town, Lafayette town, Leon town, Lincoln town, Little Falls town, Melvina village, New Lyme town. Portland town, Sparta city, Sparta town, Tomah city, Tomah town, Warrens village, and Wells town 0.629. 0.985.

89. Adams (all) 0.363; Juneau (all) 0.464; and Monroe: Byron town, Clifton town, Glendale town, Kendall village, Norwalk village, Oakdale town, Oakdale village, Ridgeville town, Scott town, Sheldon town, Wellington town, Wilton town, Wilton village, and Wyeville village 0.149. 0.976.

[jimrtex]

St. Croix 1.468, Polk 0.770, and Pierce 0.714 have a population equivalent to 2.952 districts and will be divided into three districts.

One district will be entirely in St. Croix, one district will include Polk and a portion of St.Croix (about 2/9 of the district will be in St. Croix), and one district will include Pierce and a portion of St.Croix (about 1/4 of the district will be in St.Croix). About 2/3 of St.Croix will be in the the St.Croix district.



St. Croix detail.



The St.Croix district will include the more suburban (of the Minnesota Twin Cities along the  St. Croix River. The city of River Falls is mostly in Pierce, but extends into St. Croix, and so was included in the Pierce-dominated district. New Richmond is the largest city away from the river and was placed in the St. Croix district. The more rural parts of the county were divided between the other two districts to provide population balance.

90. St.Croix: Erin Prairie town, Hudson city, Hudson town, New Richmond city, North Hudson village, Richmond town, Somerset town, Somerset village, St. Joseph town, Star Prairie town, Star Prairie village, and Troy town 0.985. 0.985.

91. Polk: (all) 0.770; and St.Croix: Baldwin town, Baldwin village, Cylon town, Deer Park village, Emerald town, Forest town, Glenwood City city, Glenwood town, Springfield town, Stanton town, Wilson village, and Woodville village 0.220. 0.990.

92. Pierce: (all) 0.714; and St.Croix: Cady town, Eau Galle town, Hammond town, Hammond village, Kinnickinnic town, Pleasant Valley town, River Falls city, Roberts village, Rush River town, Spring Valley village, and Warren town 0.263. 0.977.

[jimrtex]

Chippewa 1.087, Lincoln 0.500, and Taylor 0.360 have a population equivalent to 1.947 districts, and will have two districts. One district is entirely in Chippewa, and the other with add a small fragment of Chippewa to Taylor and Lincoln.



Chippewa detail.



98. Chippewa: (all but portion in AD-99) 0.974

99. Chippewa: Boyd village, Colburn town, Delmar town, Ruby town, and Stanley city 0.112; Lincoln (all) 0.500; and Taylor 0.360. 0.973

[Kevinstat]

Chippewa, Lincoln, and Taylor. 2 districts.

Could you humor us with an alternative where the Lincoln-Taylor-Chippewa remainder district takes in a little bit of Price (as you originally intended when you were going to keep Chippewa whole) (and perhaps a bit less (net, pop.-wise) of Chippewa) so that all three districts are with 5% of the ideal?

Were you planning on placing the two Assembly districts covering Chippewa County in a Senate district with the Price-Rusk-Sawyer-Washburn Assembly district, or some other combo?  It would be better to avoid dividing a small county like Price among both Assembly and Senate districts, of course.

[jimrtex]

Could you humor us with an alternative where the Lincoln-Taylor-Chippewa remainder district takes in a little bit of Price (as you originally intended when you were going to keep Chippewa whole) (and perhaps a bit less (net, pop.-wise) of Chippewa) so that all three districts are with 5% of the ideal?

Were you planning on placing the two Assembly districts covering Chippewa County in a Senate district with the Price-Rusk-Sawyer-Washburn Assembly district, or some other combo?  It would be better to avoid dividing a small county like Price among both Assembly and Senate districts, of course.

To have standing, you'd have to live in Price, Rusk, Sawyer, or Washburn counties.

I would threaten to move Round Lake (977) and Spider Lake (351) in northern Sawyer County to the Bayfield-Ashland-Iron-Vilas district.

The senate district will be the two Chippewa, Lincoln, Taylor districts, and the Barron-Dunn house district. Dunn gets chopped in both Assembly and Senate districts.

[Gass3268]

Winnebago 2.907 is entitled to 3 districts.

Oshkosh 1.150 is too large for one district and will have one district, with the surplus trimmed off. The Appleton suburbs: Appleton City, Menasha city and town, and Neenah city and town are too large for a district. One possibility would be to split Menasha Town, keeping the cities whole. I instead decided to split Neenah city, based on splitting the larger entity.

If the area trimmed from Neenah is on the south, and that from Oshkosh on the north, roughly 40% of the remaining district will be between Neenah and Oshkosh on the shore of Lake Winnebago.



69. Oshkosh city (part, 0.969) 0.969

70. Appleton city, Menasha city, Menasha town. and Neenah city (part, 0.357) 0.969

71. Algoma town, Black Wolf town, Clayton town, Neenah city (part, 0.087), Neenah town, Nekimi town, Nepeuskun town, Omro city, Omro town, Oshkosh city (part, 0.181), Oshkosh town, Poygan town, Rushford town, Utica town, Vinland town, Winchester town, Winneconne town, Winneconne village, and Wolf River town. 0.969

Did you figure out the splits for Neenha and Oshkosh?

[jimrtex]

Winnebago 2.907 is entitled to 3 districts.

Oshkosh 1.150 is too large for one district and will have one district, with the surplus trimmed off. The Appleton suburbs: Appleton City, Menasha city and town, and Neenah city and town are too large for a district. One possibility would be to split Menasha Town, keeping the cities whole. I instead decided to split Neenah city, based on splitting the larger entity.

If the area trimmed from Neenah is on the south, and that from Oshkosh on the north, roughly 40% of the remaining district will be between Neenah and Oshkosh on the shore of Lake Winnebago.



69. Oshkosh city (part, 0.969) 0.969

70. Appleton city, Menasha city, Menasha town. and Neenah city (part, 0.357) 0.969

71. Algoma town, Black Wolf town, Clayton town, Neenah city (part, 0.087), Neenah town, Nekimi town, Nepeuskun town, Omro city, Omro town, Oshkosh city (part, 0.181), Oshkosh town, Poygan town, Rushford town, Utica town, Vinland town, Winchester town, Winneconne town, Winneconne village, and Wolf River town. 0.969

Did you figure out the splits for Neenha and Oshkosh?

Not yet.

I'm working on Madison.

I will have to do splits on Oshkosh, Neenah, Green Bay, and Eau Claire.

[muon2]

It took few hours but I transcribed the 2016 ward results for Milwaukee from a pdf into spreadsheet. I matched the results up to the 2008 ADs as I did for 2012. That allows me to compare the PVIs for all three cycles.



AD 13 (South Milwaukee): PVI (1.3, 1.5, 0.1)
AD 14 (Franklin): PVI (-6.2, -9.1, -6.6)
AD 15 (Greenfield): PVI (-5.4, -5.9, -3.6)

The inner Dem towns along the lake shifted slightly Pub, and the southern burbs shifted a bit Dem.

AD 16 (Milwaukee - Bayview): PVI (9.5, 12.3, 15.9)
AD 17 (Milwaukee - Polonia, HVAP 51.3%): PVI (18.5, 25.2, 24.9)
AD 18 (Milwaukee - Menomonee Valley, HVAP 65.3%): PVI (27.8, 32.4, 32.6)

The Hispanic south side stayed Dem, but turnout was down about 10% from 2012.

AD 19 (West Allis): PVI (-0.3, 0.4, 0.5)
AD 20 (West Milwaukee): PVI (1.5, 4.0, 5.7)
AD 21 (Wauwatosa): PVI (-0.4, 0.0, 11.2)

Wauatosa really didn't care for Trump. Clinton picked up about 1K votes over Obama 2012, but Trump dropped 5K votes compared to Romney. Part was due to a drop in turnout from 36K to 32K and also with 2.8K third party votes - one of the highest of the ADs in my plan.

AD 22 (Milwaukee - West Side, BVAP 60.2%): PVI (35.0, 37.9, 38.8 )
AD 23 (Milwaukee - Triangle, BVAP 53.1%): PVI (32.4, 33.1, 35.9)
AD 24 (Milwaukee - Harambee, BVAP 57.1%): PVI (38.7, 39.7, 41.2)

AD 25 (Milwaukee - Capitol Heights, BVAP 62.5%): PVI (31.8, 35.7, 37.9)
AD 26 (Milwaukee - Granville, BVAP 52.3%): PVI (26.0, 29.3, 30.4)
AD 27 (Milwaukee - Havenwoods, BVAP 69.3%): PVI (35.5, 38.9, 39.4)

To look at the PVIs, the Dems seemed to do fine in the majority black ADs. But the turnout tells a far different story. In 2012 these 6 ADs generated 155K votes for Obama. In 2016 Clinton got just 123K from these ADs. That's a drop of 20%, and the difference of 32K is well in excess of the 23K margin of Trump's victory in the state. Some might argue that she lost the state right here.

AD 28 (Shorewood): PVI (13.9, 12.4, 24.0)
AD 29 (Mequon): PVI (-2.1, -2.9, 5.5)
AD 30 (Port Washington): PVI (-15.0, -17.2, -13.4)

The liberal suburbs along Milwaukee's north shore swung hard against Trump. The movement was so  much that they overwhelmed Pub-leaning Mequon in Ozaukee county. It's the only AD won by Romney in 2012 that Clinton won in 2016.

Gass - Racine and Kenosha counties don't have ward results posted for the Nov 2016 election. It's the only area I have left to process on my plan. Do you know of a source for that data by ward?

[jimrtex]

Gass - Racine and Kenosha counties don't have ward results posted for the Nov 2016 election. It's the only area I have left to process on my plan. Do you know of a source for that data by ward?

Wisconsin Elections Commission have ward results for the entire state.

[muon2]

Gass - Racine and Kenosha counties don't have ward results posted for the Nov 2016 election. It's the only area I have left to process on my plan. Do you know of a source for that data by ward?

Wisconsin Elections Commission have ward results for the entire state.

Thanks. I'm so used to going to the county authorities for data, it didn't occur to me that the state might have compiled it in one place. It certainly would have saved me time with Milwaukee had I known.

[jimrtex]

Any comments on this division of Madison? It will have four districts, so the colored areas are two districts each.



I started adding wards from the east until I got to enough population for two districts. This brought me across the isthmus, and I headed west where the street grid turned. I ended up splitting the UW campus.

So I backed up and started adding to the south. Where is the off-campus area?

Looking to a four way split, I think in the west it looks feasible to have an inner district, including UW, and then a far west district.

In the east, I will go back across the isthmus. Any thought about where to go then? Turn north towards Westport if I can complete the district. The district will be kind of an reversed S.

The minority population does not appear to be particularly concentrated. Overall, Madison is 80% WVAP, and the wards with low concentrations of whites appear to be scattered.

[jimrtex]

Reposted since the original was a while back.

Dane, Sauk, Green, Iowa, and Lafayette are entitled to 10.922 districts, or 11 whole districts with an  average population of 0.993. Eight districts will be wholly within Dane, one district will be wholly within Sauk, one district will include all of Green and a portion of Dane (roughly 65% in Green), and the other district will combine Iowa, Lafayette, the remnant of Sauk and small portion of Dane (roughly 80% in Iowa, Lafayette, and Sauk).

Initially, I determined the area of Sauk to be attached to Iowa and Lafayette. Next I determined the areas of Dane to be attached to Iowa and Green county. Finally, I divided Dane into 8 districts. Madison city is entitled to 4.060 districts, and including the enclave of Shorewood Hills village, 4.087. This can be divided into four districts, with four districts for the surrounding suburban areas.

While drawing the suburban districts, I adjusted the boundary  for the Green County based district. Originally it had kept to the southern tier of towns. But this made the suburban districts less compact and more unequal. Swapping Verona for Oregon, makes the suburban districts more compact and equal in the population.

Regional Map



Sauk County



Dane County



Madison Detail



My original plan was to include a strip in Dane along the northern edge of Green County to complete the district, but that squeezed the district based in Fitchburg. This configuration swapped Verona for Oregon, which pushes the district closer to Madison, but 2/3 of the district is in Green.

45. Dane: Belleville village, Montrose town, Perry town, Primrose town, Springdale town, Verona city, and Verona town. 0.328; Green (all) 0.641. 0.970.

AD-45 will be paired with two Rock County districts in a senate district.

I identified towns in the southern part of Sauk County that when removed made the Sauk county district at the regional average. I thin added Mount Horeb from Dane County to get to the overall target.

46. Dane: Blue Mounds town, Blue Mounds village, Mount Horeb village, and Vermont town. 0.168; Iowa (all) 0.412; Lafayette (all) 0.293; Sauk: Bear Creek town, Franklin town, Plain village, Spring Green town, Spring Green village, and Troy town. 0.107. 0.980.

47. Sauk (all except that in AD-46) 0.972.

I had originally planned to place the Sauk County district into a senate district with assembly districts to the west. This would avoid a senate chop of Sauk County. But now that Sauk is divided, I will place AD-46 with the area to the west (Grant, Vernon, Richland and Crawford) in a fairly rural district. AD-47 will be in a senate district to the north.

The eight Dane districts will be augmented by the Columbia district to form three senate districts. AD-47 will be joined to districts going northward.

Madison has enough population for four districts. A majority of the population is to the west of the isthmus. The division of the west is intended to keep the University of Wisconsin whole, and put the western end of the city in its own district.

The district that included the isthmus, and then wrapped around the west side of Lake Monona, was extended around the west shore of Lake Mendota, to the west of the airport. If it continued east, it would get to nowhere. This configuration leaves the east district fairly whole. An alternative might be to create a northeastern district, and have the other district wrap around Lake Monona is sort of an upside down U. Note the gray areas are in Madison, but have VTDs from the surrounding towns. Pretend they match the colors of the adjacent Madison districts.

48. Madison (east) (Wards 1-21, 33-34) 1.018

49. Madison (isthmus) (Wards 22-32, 35-39, 43-44. 49-59) 1.011

50. Madison (university) (Wards 40-42, 45-49, 60-75, 84) 0.996 and Shorewood Hills village 0.027. 1.023.

51. Madison (west) (Wards 76-83, 85-99) 1.035

52: Dane (east): Blooming Grove town, Cambridge village, Christiana town, Cottage Grove town, Cottage Grove village, Deerfield town, Deerfield village, Marshall village, McFarland village, Medina town, Monona city, Pleasant Springs town, Rockdale village, Stoughton city, and Sun Prairie town. 0.997

53: Dane (north) Bristol town, Burke town, Dane town, Dane village, DeForest village, Sun Prairie city,
Vienna town, Windsor town, and York town. 0.972.

54. Dane (northwest) Berry town, Black Earth town, Black Earth village, Cross Plains town, Cross Plains village, Maple Bluff village, Mazomanie town, Mazomanie village, Middleton city. Middleton town, Roxbury town, Springfield town, Waunakee village, and Westport town. 0.974.

55. Dane (south) Albion town, Brooklyn village, Dunkirk town, Dunn town, Edgerton city, Fitchburg city, Madison town, Oregon town, Oregon village, and Rutland town. 0.971.

The three western Madison districts AD-49, AD-50, and AD-51 will form one senate district.

The other Madison district AD-48 along with the southern and eastern Dane districts, AD-52 and AD-55, will form another senate district.

The northern two Dane districts, AD-53 and AD-54, will be joined with the Columbia County district to form a third senate district.

[TJ in Oregon]

Any comments on this division of Madison? It will have four districts, so the colored areas are two districts each.



I started adding wards from the east until I got to enough population for two districts. This brought me across the isthmus, and I headed west where the street grid turned. I ended up splitting the UW campus.

So I backed up and started adding to the south. Where is the off-campus area?

The on-campus area is most of Wards 45-48, 62, and 63. Wards 40-42 are mostly off-campus undergrads and Wards 43, 44, 49, 50, 61, and 65 all have large undergraduate populations in certain areas but have non-student majorities. Amusingly, one of the most obvious markers for a student area is the existence of non-negligible Republican votes.

If you're willing to use the Town of Madison as a bridge, you could move Wards 67-68 into the orange district  to keep the campus area intact. Ward 67 is a wealthy upscale leafy area and 68 is a heavily minority poorer area, so they have little to do with each other. If you can't use the Town of Madison, I'd swap 50 for 40 and 41.

Looking to a four way split, I think in the west it looks feasible to have an inner district, including UW, and then a far west district.

In the east, I will go back across the isthmus. Any thought about where to go then? Turn north towards Westport if I can complete the district. The district will be kind of an reversed S.

The minority population does not appear to be particularly concentrated. Overall, Madison is 80% WVAP, and the wards with low concentrations of whites appear to be scattered.

While orange district certainly isn't ideal, matching up the north and south sides isn't a terrible idea, as both are the closest thing Madison really has to working class minority neighborhoods. I don't forsee it being possible to draw anything even remotely resembling a minority-influenced seat.

[jimrtex]

Any comments on this division of Madison? It will have four districts, so the colored areas are two districts each.



I started adding wards from the east until I got to enough population for two districts. This brought me across the isthmus, and I headed west where the street grid turned. I ended up splitting the UW campus.

So I backed up and started adding to the south. Where is the off-campus area?

The on-campus area is most of Wards 45-48, 62, and 63. Wards 40-42 are mostly off-campus undergrads and Wards 43, 44, 49, 50, 61, and 65 all have large undergraduate populations in certain areas but have non-student majorities. Amusingly, one of the most obvious markers for a student area is the existence of non-negligible Republican votes.

If you're willing to use the Town of Madison as a bridge, you could move Wards 67-68 into the orange district  to keep the campus area intact. Ward 67 is a wealthy upscale leafy area and 68 is a heavily minority poorer area, so they have little to do with each other. If you can't use the Town of Madison, I'd swap 50 for 40 and 41.

Looking to a four way split, I think in the west it looks feasible to have an inner district, including UW, and then a far west district.

In the east, I will go back across the isthmus. Any thought about where to go then? Turn north towards Westport if I can complete the district. The district will be kind of an reversed S.

The minority population does not appear to be particularly concentrated. Overall, Madison is 80% WVAP, and the wards with low concentrations of whites appear to be scattered.

While orange district certainly isn't ideal, matching up the north and south sides isn't a terrible idea, as both are the closest thing Madison really has to working class minority neighborhoods. I don't forsee it being possible to draw anything even remotely resembling a minority-influenced seat.

I realized I had a marker for students. I had the total population for population equality, but the VAP by race for VRA purposes. But that also gives me VAP. There are some wards that are over 99.9% over 18. The angst of four 17 YO in a population of 4000 stuck studying, while everyone else is out, umm...voting.

Ward 63, the westernmost campus ward is 53% Asian. It must be on-campus graduate housing.

There is a definite increase in the under 18 population south of Regent Street. It might not happen immediately, but there must be more families as you continue south. So I swapped Wards 40 (99% adult) and 41 (100%) for Ward 50 (90%). I also swapped three wards further west between AD-50 and AD-51 for population balance. The Dane County districts are below 1.000, so keeping the maximum to 1.035 for the Madison districts is worth it.

Because of the constrained geography, it is kind of hard to balance population. You could so a bit better chopping wards.

The gray areas were in the city limits of Madison in 2010, but not in the Madison VTD's. VTD's (voting tabulation districts), but now called voting districts, are areas designated by state officials and tabulated by the census bureau. In Wisconsin, they pretty much correspond to wards, but not precisely. VTD's were frozen about 2007 and they might not have been up to date at that time. Wherever there is a Twiddlyville village and a Twiddlyville town, the VTD's corresponding to village wards will always have less population than the village population, and the VTD's corresponding to town wards will have more population than the town population.

In Madison, the VTD's for the city wards were about 5500 fewer persons than the city population. I adjusted the VTD populations for Madison (and other divided cities) based on the population in VTD's corresponding to town and other city wards. In some cases I had to guess which Madison ward they belonged to. Everywhere outside split cities, I am using the census bureau city, village, and town boundaries and populations.

The lake to the west of the southern arm of AD-50 is now in Madison (city). I could go across on the interstate (it looks like parts of it are still in the town) but it didn't really work out population-wise.

AD-50 is one of those districts that is just an agglomeration of themes. I was kind of surprised to see how many flights there were from Madison. All to regional hubs, but some quite distant such as Atlanta, Charlotte, and Denver. The airport web site is interesting in how much it is pushing the airlines that fly there. They include a calculator, where you can figure out whether the cost of driving to Mitchell or O'Hare and parking your car is worth the cheaper flights from those airports compared to Madison.

[muon2]

Any comments on this division of Madison? It will have four districts, so the colored areas are two districts each.



I started adding wards from the east until I got to enough population for two districts. This brought me across the isthmus, and I headed west where the street grid turned. I ended up splitting the UW campus.

So I backed up and started adding to the south. Where is the off-campus area?

The on-campus area is most of Wards 45-48, 62, and 63. Wards 40-42 are mostly off-campus undergrads and Wards 43, 44, 49, 50, 61, and 65 all have large undergraduate populations in certain areas but have non-student majorities. Amusingly, one of the most obvious markers for a student area is the existence of non-negligible Republican votes.

If you're willing to use the Town of Madison as a bridge, you could move Wards 67-68 into the orange district  to keep the campus area intact. Ward 67 is a wealthy upscale leafy area and 68 is a heavily minority poorer area, so they have little to do with each other. If you can't use the Town of Madison, I'd swap 50 for 40 and 41.

Looking to a four way split, I think in the west it looks feasible to have an inner district, including UW, and then a far west district.

In the east, I will go back across the isthmus. Any thought about where to go then? Turn north towards Westport if I can complete the district. The district will be kind of an reversed S.

The minority population does not appear to be particularly concentrated. Overall, Madison is 80% WVAP, and the wards with low concentrations of whites appear to be scattered.

While orange district certainly isn't ideal, matching up the north and south sides isn't a terrible idea, as both are the closest thing Madison really has to working class minority neighborhoods. I don't forsee it being possible to draw anything even remotely resembling a minority-influenced seat.

Do you see any showstopping issues in my division of Mad City? It's a 5-way split using Monona, McFarland, Middleton, and the adjacent towns to meet the population quota.

[muon2]

Here's the last part of the 2016 update of my plan, SE WI.



AD 1 (Kenosha city central): PVI (14.0, 13.5, 9.6)
AD 2 (Kenosha NW): PVI (8.1, 7.5, 2.3)
AD 3 (Pleasant Prairie): PVI (-4.5, -7.3, -12.9)

AD 4 (Racine city central): PVI (19.4, 22.5, 19.3)
AD 5 (Racine - Mt Pleasant): PVI (3.9, 3.6, 2.3)
AD 6 (Caledonia): PVI (-12.7, -14.3, -15.9)

AD 7 (Burlington): PVI (-8.0, -10.8, -14.1)
AD 8 (Elkhorn): PVI (-5.6, -9.3, -12.8 )
AD 9 (Beloit): PVI (9.3, 9.4, 3.4)

AD 10 (Janesville city central): PVI (14.3, 12.0, 8.1)
AD 11 (Edgerton): PVI (7.7, 5.7, 0.7)
AD 12 (Monroe): PVI (8.7, 6.5, -1.8 )

The shifts here are consistently towards Trump, even in some of the urban centers like Kenosha and Janesville. The areas outside of Janesville had a more marked Pub shift. Only urban Racine held close to the old PVI's.

[TJ in Oregon]

Do you see any showstopping issues in my division of Mad City? It's a 5-way split using Monona, McFarland, Middleton, and the adjacent towns to meet the population quota.

Nope. It looks like it does a good job of keeping the various parts of town intact: campus, Southwest, Far West, Near East+North, Far East. If allowable under rules for splitting cities, a 5-way split of Madison comes out a lot cleaner along neighborhood lines.

[TJ in Oregon]

I realized I had a marker for students. I had the total population for population equality, but the VAP by race for VRA purposes. But that also gives me VAP. There are some wards that are over 99.9% over 18. The angst of four 17 YO in a population of 4000 stuck studying, while everyone else is out, umm...voting.

Ward 63, the westernmost campus ward is 53% Asian. It must be on-campus graduate housing.

Yup. That's exactly what that ward is. It's pretty much all grad students and post docs with families (I'd bet the under 18% is relatively high). That area (called Eagle Heights) is surrounded by woods and the lake on every side, so it's a very quiet, removed neighborhood from the rest of campus. It would be a great place to live for someone who enjoys walking in nature.

Politically, it's rather different than the rest of campus, but probably belongs with it more than anywhere else.

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South of Regent Street, the first couple blocks are almost entirely undergraduates but by the time you get to Mound Street, it becomes almost entirely families. So Ward 50 has students but isn't really a student ward on the whole. A similar sort of thing happens when you move west through Ward 61.

The wards were drawn more based on geographic boundaries such as major roads than by the population who lives there. You'd run into a similar situation if you looked at block-level estimates for minorities in Madison.

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Well, if you do decide to go through that lake, there is a road through the UW Arboretum just south of it that one could take without absorbing any more population. There are still those small orphaned pockets of the Town of Madison in the Arboretum, but they're without road connection except through the City of Madison regardless of what you do.

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Verona, Wisconsin is home to Epic Systems, the maker of electronic medical records software. Epic regularly flies its employees to hospitals all over the country to implement their software. So Madison's airport has a lot more traffic just from Epic, than one would expect for a city this size.

[muon2]

So now I can recap the political performance of my map. The easiest measure of a plan is how the districts would vote for president compared to the two party fraction of the statewide vote.

Year	D vote share	D Seats	R Seats	D seat share
2008	57.1%	74	25	74.7%
2012	53.5%	57	42	57.6%
2016	49.6%	39	60	39.4%

The plan clearly can perform for either party depending on the vote. If proposed in 2011, the Pubs would scream that this was a map that favored Dems 3 to 1 seeing only 2008 results. By 2016 the Dems would be furious that The Pubs could win in 60 districts with barely over 50% of the vote.

One bias in the analysis is the impact of the VRA districts. Those 6 black and 1 Latino ADs tie up a lot of Dem votes. If those votes and ADs are removed from the analysis, the table becomes:

Year	D vote share	D Seats	R Seats	D seat share
2008	55.2%	67	25	72.8%
2012	51.2%	50	42	54.3%
2016	47.4%	32	60	34.8%

Now the plan looks a lot more balanced. The plan is quite elastic and highly responsive to voters. If I use a 4.5% change in the seats for each 1% change in the vote I would predict the Dems would get 68 in 2008, 51 in 2012, and 35 in 2016. At most there appears to be a one or two seat Pub bias once the effect of the VRA districts is removed. Note that the 4.5% change per 1% shift is more than twice the normal 2% effect observed in national studies of districts.

[muon2]

Part 2 - PVI analysis, Skew and Polarization

The PVI is one of the most recognized tools to place the political leanings of an area in the context of the nation as a whole adjusted for a specific year. The PVI measures a state or district's vote for one of the two major parties compared to the national vote. If the PVI stays the same it means that the state is swinging D or R at the same rate as the country as a whole. When officially reported, it's averaged over the two preceding presidential years, but I'm going to break it down year by year for the state as I did for the districts in my analysis above with negative results indicating Pub support.

Statewide
2004: +1.4
2008: +3.4
2012: +1.5
2016: -1.5
If used as an average going into each next election it would be 2012 D+2, 2016 D+2, 2020 D+0. The Trump election resulted in an average shift of 2, but a shift of 3 points when viewed from 2012 to 2016 only.

There are two metrics I use to measure a plan based on the PVI: skew and polarization. Districts are classified as even with a PVI of less than 1.5 for either party, competitive from PVI of 1.5 to 5.5, and noncompetitive beyond that. The skew compares the difference in the number of seats favoring each party (excluding those classified as even) to the expected number based on the state PVI. The polarization counts 1 for each competitive district and 2 for each noncompetitive district. Both can be expressed as a percentage of the maximum which is the number of districts for skew and twice that for polarization.

Year	State PVI	Skew	Skew %	Polarization	Polarization %
2008	+3.4	+9	+9.1%	137	69.2%
2012	+1.5	-6	-6.1%	156	78.8%
2016	-1.5	-23	-23.2%	166	83.8%

Nationally in the previous decade the polarization would typically be about 75%. The plan starts out in that range, but the trend towards a more polarized electorate is clear in this series. The hard D districts are holding and the soft districts are skewing R. The combination of the polarization along with the swing of the state compared to the nation towards the Pubs causes the plan to skew more Pub as it heads to 2016. Because of the shifting politics in the state, the plan seems to give an increasing advantage to the Pubs by a PVI measure.

As with the direct vote calculation I can remove the effect of the VRA districts on the PVI and the skew.

Year	Adj State PVI	Skew	Skew %
2008	+1.5	+9	+9.8%
2012	-0.7	-4	-4.3%
2016	-3.7	-21	-22.8%

There is now a very good correlation between the adjusted state PVI and the skew % differing by about a factor of 6. Another way of interpreting this would be to say that in this map drawn geographically to minimize chops and erosity after protecting minority districts, the skew generally tracks the PVI of the state as a whole, adjusted for the impact of those minority districts. It's important to note that because the state PVI is shifting, the skew does not directly address the fairness of the plan. The skew only says whether the plan is following overall state trends.

[Gass3268]

Do you see any showstopping issues in my division of Mad City? It's a 5-way split using Monona, McFarland, Middleton, and the adjacent towns to meet the population quota.

Nope. It looks like it does a good job of keeping the various parts of town intact: campus, Southwest, Far West, Near East+North, Far East. If allowable under rules for splitting cities, a 5-way split of Madison comes out a lot cleaner along neighborhood lines.

Agreed, this is a much cleaner split for Madison and the County. It would probably result in a UW Student getting elected to the Assembly, which would be cool.

[muon2]

Part 3 - Efficiency Gap

This thread and my plan are in response to the court decision against the current WI legislative plan. A key feature in the case used a measure called the efficiency gap to show how the plan disenfranchised Dems. The efficiency gap is based on the concept of wasted votes. A wasted vote is any vote cast for a losing candidate or on cast for a winning candidate in excess of the number of votes needed to win. In this case it's calculated by looking at each district and considering just the two-party votes cast. In that case the wasted votes in a district for the minority party are just the votes cast, and the wasted votes for the majority party are those in excess of 50% of the total two-party vote. The efficiency gap is equal to the total number of wasted Dem votes in all districts minus the number of wasted Pub votes in all districts divided by the total two-party vote in the state. The idea is that a fair map should have a small efficiency gap reflecting an even split of wasted votes between the two parties. The current WI map in 2012 was 13% and plaintiffs suggested that 7% or less would be fair.

Here's the efficiency gap for my plan in the different presidential years. Negative numbers mean more wasted Pub votes.

Year	D vote share	State PVI	Efficiency Gap
2008	57.1%	+3.4	-9.1%
2012	53.5%	+1.5	-0.4%
2016	49.6%	-1.5	+6.7%

Like the skew and seat totals the efficiency gap changed as the overall vote share. On its face, that would mean that like skew, one wouldn't want to draw a conclusion based on the efficiency gap from any one particular year. In fact, if my plan were submitted in 2011 with only 2008 to go on, it would be thought unconstitutional under the plaintiff's 7% threshold.

As with the other analyses, I can remove the VRA districts and recompute the efficiency gap.

Year	D vote share	State PVI	Efficiency Gap
2008	55.2%	+1.5	-11.2%
2012	51.2%	-0.7	-0.9%
2016	47.4%	-3.7	+10.6%

Unlike the other analyses that saw a consistent shift as the VRA districts were removed, the efficiency gap instead spreads the results, favoring the Dems more in years that supported Dems and Pubs more in years that supported Pubs. The efficiency gap numbers don't correlate that well to either the D vote share or to the PVI.

As I drill into the numbers some strange things come to light. In general the losing party has more wasted votes. If there were 100 votes in just one district and they split 60 - 40 then the gap would be (40-10)/100 = 30%. If they split 70 - 30 the gap would be (30-20)/100 = 10% so the efficiency gap drops as the district becomes more polarized. At a split of 75 - 25 the wasted votes are equal and there is no contribution to the gap. If the split goes higher than 75% then the majority party starts to have more wasted votes, which is exactly what happens in the VRA districts.

As the districts become more competitive they start to have a greater and greater effect on the efficiency gap. A 55 - 45 district has a gap of (45-5)/100 = 40% and a 51 - 49 district has a gap of (49-1)/100 = 48%. If that close district has a 2 point swing to the minority party, they become the majority and suddenly the gap is 48% in the other direction. This kind of jump discontinuity in results is disfavored in models since one doesn't want small changes in the vote to result in big jumps in the score. Because my plan as a reasonable number of competitive and even districts that switched parties between the three elections, it sees big jumps in the efficiency gap. In any case the efficiency gap sheds little light as to whether my plan is fair or not.

Given these observations, if an efficiency gap standard were the official measure, then map makers should try to have as many safe districts as possible without exceeding 75% of the two-party vote. Minority districts should be kept as close to a 75% Dem majority as possible. By all means very competitive districts should be avoided since they will make a good plan look bad after any wave year by dumping lots of wasted votes from one party to the other. This does not seem like a sound measure for general use in redistricting.

The current WI plan is certainly biased in favor of the Pubs. I don't think the efficiency gap is the right tool to discard it, and it could lead to some very unintended consequences if used to assess a plan in the way I have here.