2020 Redistricting in Pennsylvania

[lfromnj]

@blarite, did you split the city of Pittsburgh?

Nope:

Works fine, can't make any major disagreements. I had Penn hills and Mt. Lebanon switched  but was honestly just a bit lazy over there.

I have some issues with your Lehigh valley seats but I can see how you were forced to create that due to other decisions you made. Not perfectly happy with Lancaster but the problem with Lancaster is its pretty big but not big enough to be a whole CD. The same problem exists in SC with Spartanburg and Greensville,

[President Punxsutawney Phil]

My effort at a fair PA. Shading is of 2012/2016 PVI, but for some reason seems to not be purely based on said metric? County splits are kept to the minimum when possible. Both Lehigh and Scranton CDs have very light R+ PVIs, at R+1.5 or less. PA-06 is not prevented from becoming R leaning; it becomes R+2.5. The Pittsburgh CD now takes in all of Pittsburgh+all of Allegheny south of and east of the three-way rivers except Dravosburg+about 57k in Washington County. PA-16, successor to old PA-17, moves about 1 point to the left due to the Pittsburgh CD following river boundaries.
https://davesredistricting.org/join/500e7b37-b19d-4fc8-afd0-cb8209ef30c5
DRA link

[Pericles]

I don't regard a map as being fair if it's not proportional and accurately translates votes into election results. At some level FPP can't be fair, which is why I oppose FPP, but map-makers should try to make FPP as fair as possible.

[Southern Senator North Carolina Yankee]

I don't regard a map as being fair if it's not proportional and accurately translates votes into election results. At some level FPP can't be fair, which is why I oppose FPP, but map-makers should try to make FPP as fair as possible.

Assuming you are responding to Tim, 9-8 with a bunch of swing seats is very reasonable for an R+1/2 state like PA.

[Pericles]

I don't regard a map as being fair if it's not proportional and accurately translates votes into election results. At some level FPP can't be fair, which is why I oppose FPP, but map-makers should try to make FPP as fair as possible.

Assuming you are responding to Tim, 9-8 with a bunch of swing seats is very reasonable for an R+1/2 state like PA.

Oh I saw Blairite's one which he described as "peak fair map performance", seems very unfair to me.

[Starry Eyed Jagaloon]

I don't regard a map as being fair if it's not proportional and accurately translates votes into election results. At some level FPP can't be fair, which is why I oppose FPP, but map-makers should try to make FPP as fair as possible.

Assuming you are responding to Tim, 9-8 with a bunch of swing seats is very reasonable for an R+1/2 state like PA.

Oh I saw Blairite's one which he described as "peak fair map performance", seems very unfair to me.

To be fair, Dems would currently hold 9/17 seats on my map, though it would likely drop to 5/17 in 2022. I don't love the outcome but most fair maps prioritize compactness and COIs with it all eventually balancing out partisanship-wise when you add every state up.

[Former President tack50]

Annoyingly, a fair 17-district map in PA only produces 5 Safe D districts (2 in Philly, MontCo, DelCo, and Pittsburgh.) You may not like it (I certainly don't) but this is what peak fair map performance looks like:

Hate to beat this CRR drum here, but imagine what could be done with ~28 seats?

PA has a problem since all of its D votes are packed into tight little circles, so larger districts done without spaghetti strips drowns them all out. Smaller districts on the other hand make things more interesting.

Doesn't really change all that much?

The problem for Democrats is really that US cities now vote like they belong in North Korea or Saddam Hussein's Irak (80-20 or more); while the Republican areas are more numerous and vote on the scale of 60-40 (comfortable victories, but without wasting votes)

A hypothetically fair 28 district map might look something like this



This map would have 8 "bomb proof" Democratic seats (6 in the Philadelphia area, 1 Allentown and 1 Pittsburgh); as well as 3-4 others that would be a heavy lift for an R candidate but aren't truly safe (D+2 PVI).

Blairite's map gives Dems 29% of the seats in "bombproof" seats. This map gives them 29% as well. The main difference is that instead of a bunch of Lean R seats, after that you get several Lean D seats instead.

Overall I don't think it makes a particular difference to increase the number of seats (depends on the state)

[President Punxsutawney Phil]

I don't regard a map as being fair if it's not proportional and accurately translates votes into election results. At some level FPP can't be fair, which is why I oppose FPP, but map-makers should try to make FPP as fair as possible.

Assuming you are responding to Tim, 9-8 with a bunch of swing seats is very reasonable for an R+1/2 state like PA.

Thoughts on my 17 seat fair map?

[palandio]

I'm currently doing a 51-seat map for Pennsylvania. With 51 seats things are not that bad for Democrats:

17 seats in SEPA, of which 16 are tilt D to safe D (by 2012/2016 PVI), one is tilt R

5 seats in Allegheny County, of which 3 are lean to safe D, while the two R-leaning ones are trending D

Scranton (D+6)
Allentown (D+4)
Erie (D+4)
Reading (D+3)
Harrisburg (D+3)
Bethlehem (tossup)
Easton, Stroudsburg (tossup)
Lancaster (R+1)
Wilkes-Barre (R+3)
State College (R+5)


19 likely to safe R

[President Punxsutawney Phil]

I'm currently doing a 51-seat map for Pennsylvania. With 51 seats things are not that bad for Democrats:

17 seats in SEPA, of which 16 are tilt D to safe D (by 2012/2016 PVI), one is tilt R

5 seats in Allegheny County, of which 3 are lean to safe D, while the two R-leaning ones are trending D

Scranton (D+6)
Allentown (D+4)
Erie (D+4)
Reading (D+3)
Harrisburg (D+3)
Bethlehem (tossup)
Easton, Stroudsburg (tossup)
Lancaster (R+1)
Wilkes-Barre (R+3)
State College (R+5)


19 likely to safe R

Isn't this basically a state senate map?

[Idaho Conservative]

Honestly find a way to Chop Cartwright and give the best parts of Lackawanna to Wild while Fitzpatrick takes  the redder parts of the Lehigh Valley so Houlahan can keep more of Chester.  Everyone besides Cartwright should be pretty happy.



Here we go, Cartwright is effectively chopped as Mueser/Wild eat up his district.

Houlahan manages to keep a +5 D composite district while Fitzpatrick's district moves moderately to the right. Wild gets a pretty Safe district at +15 composit although probably only +8 Clinton although double digit Biden.

Dean takes a light hit but its still clearly Safe D even without Lower Merion.

I don't think the Dems would agree to cutting Cartwright when that seat fits so naturally there.

[palandio]

I'm currently doing a 51-seat map for Pennsylvania. With 51 seats things are not that bad for Democrats:

17 seats in SEPA, of which 16 are tilt D to safe D (by 2012/2016 PVI), one is tilt R

5 seats in Allegheny County, of which 3 are lean to safe D, while the two R-leaning ones are trending D

Scranton (D+6)
Allentown (D+4)
Erie (D+4)
Reading (D+3)
Harrisburg (D+3)
Bethlehem (tossup)
Easton, Stroudsburg (tossup)
Lancaster (R+1)
Wilkes-Barre (R+3)
State College (R+5)


19 likely to safe R

Isn't this basically a state senate map?

You're right. So I should better draw a State Senate map with 50 seats instead of 51 seats.

What this probably means is that with a ~50-seat map the Democrats' geographic disadvantage is smaller than with 17 or 18 seats. The current Pennsylvania State Senate has of course 28 Republicans and 21 Democrats (22 elected as Democrats) which would point to a R advantage.

How do the single areas compare?

SEPA has 14 Democrats which is close to the ceiling except for the 6th where Tomlinson seems to be a strong R incumbent in a D-leaning seat.

Allegheny has 4 Democrats, the 38th and the 43rd seem to be tossups, as expected (one D-held, one R-held).

Scranton is D.
Reading is D.
The Allentown/Bethlehem/Easton area has only one Democrat, due to both the Bethlehem/Easton seat being a D pack and Browne being a strong incumbent in the 16th.

Erie hasd Republican Laughlin elected in a D-leaning seat in 2016.
Harrisburg is drawn less favorably for the Democrats than is could be, Republican DiSanto gained this seat in 2016.
Lancaster is in traditionally R territory.
Wilkes-Barre elected Yudichak, but he left the Democrats.

Hence most of the Democrats' disadvantage is due to three Republicans in D-leaning seats and some is due to the map being drawn unfavorably for them (Harrisburg, Allentown).

[President Punxsutawney Phil]

I'm currently doing a 51-seat map for Pennsylvania. With 51 seats things are not that bad for Democrats:

17 seats in SEPA, of which 16 are tilt D to safe D (by 2012/2016 PVI), one is tilt R

5 seats in Allegheny County, of which 3 are lean to safe D, while the two R-leaning ones are trending D

Scranton (D+6)
Allentown (D+4)
Erie (D+4)
Reading (D+3)
Harrisburg (D+3)
Bethlehem (tossup)
Easton, Stroudsburg (tossup)
Lancaster (R+1)
Wilkes-Barre (R+3)
State College (R+5)


19 likely to safe R

Isn't this basically a state senate map?

You're right. So I should better draw a State Senate map with 50 seats instead of 51 seats.

What this probably means is that with a ~50-seat map the Democrats' geographic disadvantage is smaller than with 17 or 18 seats. The current Pennsylvania State Senate has of course 28 Republicans and 21 Democrats (22 elected as Democrats) which would point to a R advantage.

How do the single areas compare?

SEPA has 14 Democrats which is close to the ceiling except for the 6th where Tomlinson seems to be a strong R incumbent in a D-leaning seat.

Allegheny has 4 Democrats, the 38th and the 43rd seem to be tossups, as expected (one D-held, one R-held).

Scranton is D.
Reading is D.
The Allentown/Bethlehem/Easton area has only one Democrat, due to both the Bethlehem/Easton seat being a D pack and Browne being a strong incumbent in the 16th.

Erie hasd Republican Laughlin elected in a D-leaning seat in 2016.
Harrisburg is drawn less favorably for the Democrats than is could be, Republican DiSanto gained this seat in 2016.
Lancaster is in traditionally R territory.
Wilkes-Barre elected Yudichak, but he left the Democrats.

Hence most of the Democrats' disadvantage is due to three Republicans in D-leaning seats and some is due to the map being drawn unfavorably for them (Harrisburg, Allentown).

How much priority do you place on reducing the # of county splits?

[palandio]

[...]
How much priority do you place on reducing the # of county splits?

That's a difficult question. Generally I would say that reducing county splits is desirable and that a map that has many more splits than necessary is in most cases a bad map. On the other hand a good map is defined by more than just reducing splits: Representing CoIs, compactness, reasonable responsiveness to swings, a certain degree of partisan balance, etc. The optimal map may in many cases have slightly more than the mininally possible number of county splits.

[Boss_Rahm]

Hate to beat this CRR drum here, but imagine what could be done with ~28 seats?

PA has a problem since all of its D votes are packed into tight little circles, so larger districts done without spaghetti strips drowns them all out. Smaller districts on the other hand make things more interesting.

Here's a 16-12 D gerrymander I've drawn (using 2010 population figures). There are just 26 county splits and Pittsburgh is kept whole.

https://davesredistricting.org/join/856864b1-aeb8-4996-ab0c-124dc75cb423

[President Punxsutawney Phil]

Hate to beat this CRR drum here, but imagine what could be done with ~28 seats?

PA has a problem since all of its D votes are packed into tight little circles, so larger districts done without spaghetti strips drowns them all out. Smaller districts on the other hand make things more interesting.

Here's a 16-12 D gerrymander I've drawn (using 2010 population figures). There are just 26 county splits and Pittsburgh is kept whole.

https://davesredistricting.org/join/856864b1-aeb8-4996-ab0c-124dc75cb423

Interesting. I would have expected you feeding Pittsburgh in to areas farther north, since northern Allegheny is the most R area in the county. But the way you have it also makes sense.

[Boss_Rahm]

Hate to beat this CRR drum here, but imagine what could be done with ~28 seats?

PA has a problem since all of its D votes are packed into tight little circles, so larger districts done without spaghetti strips drowns them all out. Smaller districts on the other hand make things more interesting.

Here's a 16-12 D gerrymander I've drawn (using 2010 population figures). There are just 26 county splits and Pittsburgh is kept whole.

https://davesredistricting.org/join/856864b1-aeb8-4996-ab0c-124dc75cb423

Interesting. I would have expected you feeding Pittsburgh in to areas farther north, since northern Allegheny is the most R area in the county. But the way you have it also makes sense.

You're right, I suppose a more effective gerrymander would have a district snaking around from Beaver County to the Mon River valley. I did want to maintain some amount of compactness in my map.

[President Punxsutawney Phil]

Hate to beat this CRR drum here, but imagine what could be done with ~28 seats?

PA has a problem since all of its D votes are packed into tight little circles, so larger districts done without spaghetti strips drowns them all out. Smaller districts on the other hand make things more interesting.

Here's a 16-12 D gerrymander I've drawn (using 2010 population figures). There are just 26 county splits and Pittsburgh is kept whole.

https://davesredistricting.org/join/856864b1-aeb8-4996-ab0c-124dc75cb423

Interesting. I would have expected you feeding Pittsburgh in to areas farther north, since northern Allegheny is the most R area in the county. But the way you have it also makes sense.

You're right, I suppose a more effective gerrymander would have a district snaking around from Beaver County to the Mon River valley. I did want to maintain some amount of compactness in my map.

Is it really the case that this would hurt compactness that much though?

[Boss_Rahm]

Hate to beat this CRR drum here, but imagine what could be done with ~28 seats?

PA has a problem since all of its D votes are packed into tight little circles, so larger districts done without spaghetti strips drowns them all out. Smaller districts on the other hand make things more interesting.

Here's a 16-12 D gerrymander I've drawn (using 2010 population figures). There are just 26 county splits and Pittsburgh is kept whole.

https://davesredistricting.org/join/856864b1-aeb8-4996-ab0c-124dc75cb423

Interesting. I would have expected you feeding Pittsburgh in to areas farther north, since northern Allegheny is the most R area in the county. But the way you have it also makes sense.

You're right, I suppose a more effective gerrymander would have a district snaking around from Beaver County to the Mon River valley. I did want to maintain some amount of compactness in my map.

Is it really the case that this would hurt compactness that much though?

Okay, I made your suggested changes in Allegheny County (and fiddled with Chester County while I was at it). I'm happy with this version.
https://davesredistricting.org/join/856864b1-aeb8-4996-ab0c-124dc75cb423

[President Punxsutawney Phil]

Hate to beat this CRR drum here, but imagine what could be done with ~28 seats?

PA has a problem since all of its D votes are packed into tight little circles, so larger districts done without spaghetti strips drowns them all out. Smaller districts on the other hand make things more interesting.

Here's a 16-12 D gerrymander I've drawn (using 2010 population figures). There are just 26 county splits and Pittsburgh is kept whole.

https://davesredistricting.org/join/856864b1-aeb8-4996-ab0c-124dc75cb423

Interesting. I would have expected you feeding Pittsburgh in to areas farther north, since northern Allegheny is the most R area in the county. But the way you have it also makes sense.

You're right, I suppose a more effective gerrymander would have a district snaking around from Beaver County to the Mon River valley. I did want to maintain some amount of compactness in my map.

Is it really the case that this would hurt compactness that much though?

Okay, I made your suggested changes in Allegheny County (and fiddled with Chester County while I was at it). I'm happy with this version.
https://davesredistricting.org/join/856864b1-aeb8-4996-ab0c-124dc75cb423

iirc, didn't the old map have a Pittsburgh CD that is D+17? Meaning this lowers the Dem PVI a few points (not that it's a bad thing. It's a good thing)?

[Boss_Rahm]

Hate to beat this CRR drum here, but imagine what could be done with ~28 seats?

PA has a problem since all of its D votes are packed into tight little circles, so larger districts done without spaghetti strips drowns them all out. Smaller districts on the other hand make things more interesting.

Here's a 16-12 D gerrymander I've drawn (using 2010 population figures). There are just 26 county splits and Pittsburgh is kept whole.

https://davesredistricting.org/join/856864b1-aeb8-4996-ab0c-124dc75cb423

Interesting. I would have expected you feeding Pittsburgh in to areas farther north, since northern Allegheny is the most R area in the county. But the way you have it also makes sense.

You're right, I suppose a more effective gerrymander would have a district snaking around from Beaver County to the Mon River valley. I did want to maintain some amount of compactness in my map.

Is it really the case that this would hurt compactness that much though?

Okay, I made your suggested changes in Allegheny County (and fiddled with Chester County while I was at it). I'm happy with this version.
https://davesredistricting.org/join/856864b1-aeb8-4996-ab0c-124dc75cb423

iirc, didn't the old map have a Pittsburgh CD that is D+17? Meaning this lowers the Dem PVI a few points (not that it's a bad thing. It's a good thing)?

I didn't keep track of the Pittsburgh CD, but the two suburban CDs each moved about a point left, so that sounds right.

[Thunder98 🇮🇱 🤝 🇵🇸]

Here is my 10 R - 7 D map based on the 2012-2016 pres results. I really hope DRA adds the 2016 and 2018 elections on there and soon the 2020 election results for PA.

[S019]

Here is my 10 R - 7 D map based on the 2012-2016 pres results. I really hope DRA adds the 2016 and 2018 elections on there and soon the 2020 election results for PA.

Districtr has 2016 results, so if you want 2016 results for your map, just redraw it there, it is a pain, but it works

[EastAnglianLefty]

I'm currently doing a 51-seat map for Pennsylvania. With 51 seats things are not that bad for Democrats:

17 seats in SEPA, of which 16 are tilt D to safe D (by 2012/2016 PVI), one is tilt R

5 seats in Allegheny County, of which 3 are lean to safe D, while the two R-leaning ones are trending D

Scranton (D+6)
Allentown (D+4)
Erie (D+4)
Reading (D+3)
Harrisburg (D+3)
Bethlehem (tossup)
Easton, Stroudsburg (tossup)
Lancaster (R+1)
Wilkes-Barre (R+3)
State College (R+5)


19 likely to safe R

Isn't this basically a state senate map?

You're right. So I should better draw a State Senate map with 50 seats instead of 51 seats.

What this probably means is that with a ~50-seat map the Democrats' geographic disadvantage is smaller than with 17 or 18 seats. The current Pennsylvania State Senate has of course 28 Republicans and 21 Democrats (22 elected as Democrats) which would point to a R advantage.

How do the single areas compare?

SEPA has 14 Democrats which is close to the ceiling except for the 6th where Tomlinson seems to be a strong R incumbent in a D-leaning seat.

Allegheny has 4 Democrats, the 38th and the 43rd seem to be tossups, as expected (one D-held, one R-held).

Scranton is D.
Reading is D.
The Allentown/Bethlehem/Easton area has only one Democrat, due to both the Bethlehem/Easton seat being a D pack and Browne being a strong incumbent in the 16th.

Erie hasd Republican Laughlin elected in a D-leaning seat in 2016.
Harrisburg is drawn less favorably for the Democrats than is could be, Republican DiSanto gained this seat in 2016.
Lancaster is in traditionally R territory.
Wilkes-Barre elected Yudichak, but he left the Democrats.

Hence most of the Democrats' disadvantage is due to three Republicans in D-leaning seats and some is due to the map being drawn unfavorably for them (Harrisburg, Allentown).

This is what I came up with for the state senate: https://davesredistricting.org/join/f38b31b1-1fa9-4412-9221-6347e1778457

Basic assumptions were clean lines, keeping urban areas together and maximising the number of VRA seats in SE PA. Twenty-two districts have a D PVI in 2016, 28 had an R PVI. The tipping point seat is a little over R+4. That might have improved a little in 2020 given trends, but it'll still be at least a couple of points R.

[palandio]

[...]

This is what I came up with for the state senate: https://davesredistricting.org/join/f38b31b1-1fa9-4412-9221-6347e1778457

Basic assumptions were clean lines, keeping urban areas together and maximising the number of VRA seats in SE PA. Twenty-two districts have a D PVI in 2016, 28 had an R PVI. The tipping point seat is a little over R+4. That might have improved a little in 2020 given trends, but it'll still be at least a couple of points R.

Yes, that map makes a lot of sense in so many places.

But it can also be tweaked into the Democrats' direction in a few places. I did a rearrangement of districts in Bucks/Montgomery and Allegheny in the following way (first comes EastAnglianLefty's proposal, then my own):




The new Bucks Central seat is mostly D-trending suburbs, it actually voted for Clinton (and it makes a lot of sense as a CoI). The district in Northern Bucks and Northern Montgomery serves mostly as a Republican vote sink, a case of quite blatant gerrymandering and I'm not sure whether it is a wise thing to do. The two long-ish districts in Montogomery are aesthetically meh, but I have seen much worse creations. The Southern Bucks district should be clearly D-leaning, but who knows with a R candidate like Fitzgerald or Tomlinson.




A setup that is at the same time a clear tweak in the Democrat's favor and very aesthetically pleasing. The South-Eastern district which has less favorable trends for the Democrats is given a safety margin. All Allegheny districts voted for Clinton. The main problem that I see is that African American influence is diluted compared to EastAnglianLefty's proposal.

What does this mean overall?

Democrats have 13 seats with a PVI >5 (11 in SEPA, 1 in Pittsburgh, 1 in Allentown)

Then you have:
14. Allegheny SE D+5 (Clinton +8)
15. Scranton D+5 (Clinton +0)
16. Bucks South D+4 (Clinton +7)
17. Harrisburg D+4 (Clinton +10)
18. Erie D+3 (Clinton +1)
19. Reading D+2 (Clinton +4)
20. Chester NE D+2 (Clinton +13)
21. Allegheny NE D+2 (Clinton +7)
22. Bethlehem, Easton EVEN (Clinton +0)
23. Chester SW EVEN (Clinton +6)
24. Allegheny NW EVEN (Clinton +6)
25. Allegheny SW EVEN (Clinton +5)
26. Lancaster R+1 (Clinton +2)
27. Bucks Central R+2 (Clinton +3)

That is 27 Clinton districts (although she won three of them by less than one percentage point). Seems like a level playing field to me.