Big Redistricting News Out Of PA!

[politicallefty]

For a plan with N districts, there should not be more than N-1 county chops without a clearly definable reason. In a state like PA with lots of well defined cities, towns and Philly wards (identified by the names of the vote districts in DRA) there is no reason other than trying for exact population equality to chop any of them. Doing so divides a community of interest (less so with some of the wards). There are enough of those county subdivisions that it should always be possible to get within a relatively small deviation, probably under 1000 and certainly less than 0.5%.

The five Philly area counties plus Berks and Lancaster are a near perfect fit for 7 CDs with 2010 data. There should be no more than 6 chops in those counties, and this plan does that (3 chops in Philly, 1 each in Montco, Delco, and Chester. I don't know if towns and wards were preserved whole though, but I presume some minor adjustments could be made to respect those lines.

The county splits out west are a different matter. I know ASV said he thought the communities of interest are more important, but I'm not how that applies there. The western boundary of Cambria and Somerset counties is a significant mountain ridge that is largely protected by state forests. It seems that this plan tries to use the next, lower ridge to the west as the line separating communities of interest, but that doesn't comport with the actually lifestyle patterns in that part of the state from my visits. Those county lines in this case do a pretty good job of marking the separation between regions.

I think that PA-01 is a violation of any fair and reasonable map. Philadelphia has the population for at least two districts. I think that should require, in any fair map, that the city/county should have two districts within its boundaries. That does mean an additional chop of Chester, however I believe the preceding criteria should take precedence. And furthermore, I think the other problem with SEPA in that map is that PA-13 takes in two non-contiguous parts of Philadelphia.

Like I said, I don't think it's an overall unreasonable map apart from what I mentioned above. It just needs some cleaning up in terms of county splits. I would work on it myself, but I don't want to start from scratch. To start, I would swap numbering between PA-11 and PA-17 and I would make the new PA-11 a Lackawanna/Luzerne/Monroe district.

[jimrtex]

The county splits out west are a different matter. I know ASV said he thought the communities of interest are more important, but I'm not how that applies there. The western boundary of Cambria and Somerset counties is a significant mountain ridge that is largely protected by state forests. It seems that this plan tries to use the next, lower ridge to the west as the line separating communities of interest, but that doesn't comport with the actually lifestyle patterns in that part of the state from my visits. Those county lines in this case do a pretty good job of marking the separation between regions.

If we were using significant mountain ridges, we would use Allegheny Mountain (Eastern Continental Mountain Divide), but that would split Altoona and Johnstown, which with modern transportation by rail and interstate do form a community of interest.

I do agree with your concern about splitting 3 counties to follow a ridge that wasn't important enough to be used for county boundaries in a state where ridges form boundaries to the extent that the counties look misshapen.

[muon2]

For a plan with N districts, there should not be more than N-1 county chops without a clearly definable reason. In a state like PA with lots of well defined cities, towns and Philly wards (identified by the names of the vote districts in DRA) there is no reason other than trying for exact population equality to chop any of them. Doing so divides a community of interest (less so with some of the wards). There are enough of those county subdivisions that it should always be possible to get within a relatively small deviation, probably under 1000 and certainly less than 0.5%.

The five Philly area counties plus Berks and Lancaster are a near perfect fit for 7 CDs with 2010 data. There should be no more than 6 chops in those counties, and this plan does that (3 chops in Philly, 1 each in Montco, Delco, and Chester. I don't know if towns and wards were preserved whole though, but I presume some minor adjustments could be made to respect those lines.

The county splits out west are a different matter. I know ASV said he thought the communities of interest are more important, but I'm not how that applies there. The western boundary of Cambria and Somerset counties is a significant mountain ridge that is largely protected by state forests. It seems that this plan tries to use the next, lower ridge to the west as the line separating communities of interest, but that doesn't comport with the actually lifestyle patterns in that part of the state from my visits. Those county lines in this case do a pretty good job of marking the separation between regions.

I think that PA-01 is a violation of any fair and reasonable map. Philadelphia has the population for at least two districts. I think that should require, in any fair map, that the city/county should have two districts within its boundaries. That does mean an additional chop of Chester, however I believe the preceding criteria should take precedence. And furthermore, I think the other problem with SEPA in that map is that PA-13 takes in two non-contiguous parts of Philadelphia.

Like I said, I don't think it's an overall unreasonable map apart from what I mentioned above. It just needs some cleaning up in terms of county splits. I would work on it myself, but I don't want to start from scratch. To start, I would swap numbering between PA-11 and PA-17 and I would make the new PA-11 a Lackawanna/Luzerne/Monroe district.

There is a school of thought that says one redistricting principle should be: In any county greater than the population for a whole district there should be a number of districts completely within the county equal to the population of the county divided by the quota for one district, rounded down to the nearest whole number. In PA that would require 2 CDs in wholly in Philly, 1 wholly in Montco, and 1 wholly in Allegheny.

We debated the merits of this principle on threads on this board back in 2012-13. In the end the majority view here was that a count of the total number of chops was a more important principle than considering how the fragments of the chops nested within counties. I shared that view in part from my experience in the 2011 OH Redistricting Competition, which had nesting requirements for legislative districts and rules that created a preference for wholly-contained districts in the congressional plan. I thought it created unneeded skews to other measures of the plan.

[AustralianSwingVoter]

For a plan with N districts, there should not be more than N-1 county chops without a clearly definable reason. In a state like PA with lots of well defined cities, towns and Philly wards (identified by the names of the vote districts in DRA) there is no reason other than trying for exact population equality to chop any of them. Doing so divides a community of interest (less so with some of the wards). There are enough of those county subdivisions that it should always be possible to get within a relatively small deviation, probably under 1000 and certainly less than 0.5%.

The five Philly area counties plus Berks and Lancaster are a near perfect fit for 7 CDs with 2010 data. There should be no more than 6 chops in those counties, and this plan does that (3 chops in Philly, 1 each in Montco, Delco, and Chester. I don't know if towns and wards were preserved whole though, but I presume some minor adjustments could be made to respect those lines.

The county splits out west are a different matter. I know ASV said he thought the communities of interest are more important, but I'm not how that applies there. The western boundary of Cambria and Somerset counties is a significant mountain ridge that is largely protected by state forests. It seems that this plan tries to use the next, lower ridge to the west as the line separating communities of interest, but that doesn't comport with the actually lifestyle patterns in that part of the state from my visits. Those county lines in this case do a pretty good job of marking the separation between regions.

I think that PA-01 is a violation of any fair and reasonable map. Philadelphia has the population for at least two districts. I think that should require, in any fair map, that the city/county should have two districts within its boundaries. That does mean an additional chop of Chester, however I believe the preceding criteria should take precedence. And furthermore, I think the other problem with SEPA in that map is that PA-13 takes in two non-contiguous parts of Philadelphia.

Like I said, I don't think it's an overall unreasonable map apart from what I mentioned above. It just needs some cleaning up in terms of county splits. I would work on it myself, but I don't want to start from scratch. To start, I would swap numbering between PA-11 and PA-17 and I would make the new PA-11 a Lackawanna/Luzerne/Monroe district.

There is a school of thought that says one redistricting principle should be: In any county greater than the population for a whole district there should be a number of districts completely within the county equal to the population of the county divided by the quota for one district, rounded down to the nearest whole number. In PA that would require 2 CDs in wholly in Philly, 1 wholly in Montco, and 1 wholly in Allegheny.

We debated the merits of this principle on threads on this board back in 2012-13. In the end the majority view here was that a count of the total number of chops was a more important principle than considering how the fragments of the chops nested within counties. I shared that view in part from my experience in the 2011 OH Redistricting Competition, which had nesting requirements for legislative districts and rules that created a preference for wholly-contained districts in the congressional plan. I thought it created unneeded skews to other measures of the plan.

PA-1 and 2 could be entirely within Philly County, however I should have made it clearer that the arrangement exists solely to allow for 2 Black Majority congressional districts in Philly.

[muon2]

For a plan with N districts, there should not be more than N-1 county chops without a clearly definable reason. In a state like PA with lots of well defined cities, towns and Philly wards (identified by the names of the vote districts in DRA) there is no reason other than trying for exact population equality to chop any of them. Doing so divides a community of interest (less so with some of the wards). There are enough of those county subdivisions that it should always be possible to get within a relatively small deviation, probably under 1000 and certainly less than 0.5%.

The five Philly area counties plus Berks and Lancaster are a near perfect fit for 7 CDs with 2010 data. There should be no more than 6 chops in those counties, and this plan does that (3 chops in Philly, 1 each in Montco, Delco, and Chester. I don't know if towns and wards were preserved whole though, but I presume some minor adjustments could be made to respect those lines.

The county splits out west are a different matter. I know ASV said he thought the communities of interest are more important, but I'm not how that applies there. The western boundary of Cambria and Somerset counties is a significant mountain ridge that is largely protected by state forests. It seems that this plan tries to use the next, lower ridge to the west as the line separating communities of interest, but that doesn't comport with the actually lifestyle patterns in that part of the state from my visits. Those county lines in this case do a pretty good job of marking the separation between regions.

I think that PA-01 is a violation of any fair and reasonable map. Philadelphia has the population for at least two districts. I think that should require, in any fair map, that the city/county should have two districts within its boundaries. That does mean an additional chop of Chester, however I believe the preceding criteria should take precedence. And furthermore, I think the other problem with SEPA in that map is that PA-13 takes in two non-contiguous parts of Philadelphia.

Like I said, I don't think it's an overall unreasonable map apart from what I mentioned above. It just needs some cleaning up in terms of county splits. I would work on it myself, but I don't want to start from scratch. To start, I would swap numbering between PA-11 and PA-17 and I would make the new PA-11 a Lackawanna/Luzerne/Monroe district.

There is a school of thought that says one redistricting principle should be: In any county greater than the population for a whole district there should be a number of districts completely within the county equal to the population of the county divided by the quota for one district, rounded down to the nearest whole number. In PA that would require 2 CDs in wholly in Philly, 1 wholly in Montco, and 1 wholly in Allegheny.

We debated the merits of this principle on threads on this board back in 2012-13. In the end the majority view here was that a count of the total number of chops was a more important principle than considering how the fragments of the chops nested within counties. I shared that view in part from my experience in the 2011 OH Redistricting Competition, which had nesting requirements for legislative districts and rules that created a preference for wholly-contained districts in the congressional plan. I thought it created unneeded skews to other measures of the plan.

PA-1 and 2 could be entirely within Philly County, however I should have made it clearer that the arrangement exists solely to allow for 2 Black Majority congressional districts in Philly.

The 2010 Census had 665K blacks (including Hispanic blacks) in the city of Philadelphia. The 2010 Census set a quota of 706K per CD. The black population in Philly isn't large enough to be the majority in 2 CDs.

[politicallefty]

There is a school of thought that says one redistricting principle should be: In any county greater than the population for a whole district there should be a number of districts completely within the county equal to the population of the county divided by the quota for one district, rounded down to the nearest whole number. In PA that would require 2 CDs in wholly in Philly, 1 wholly in Montco, and 1 wholly in Allegheny.

We debated the merits of this principle on threads on this board back in 2012-13. In the end the majority view here was that a count of the total number of chops was a more important principle than considering how the fragments of the chops nested within counties. I shared that view in part from my experience in the 2011 OH Redistricting Competition, which had nesting requirements for legislative districts and rules that created a preference for wholly-contained districts in the congressional plan. I thought it created unneeded skews to other measures of the plan.

I'm not sure I necessarily agree, but I admit I haven't fully explored the issue. I have always considered it a high priority when I've drawn maps. For PA, I have always followed the requirements you noted of that criteria. For OH, that would mean one district each entirely contained within each of Cuyahoga, Franklin, and Hamilton Counties. I don't really see a strong argument against having such a standard.

In this case, however, the two criteria are not in conflict (unless chopping a county an additional time violates certain criteria). In the map we're discussing, the districts basically move counter-clockwise. PA-01 moves out of Delco, eliminating the chop of that county. And ultimately, through a number of changes, PA-06 moves into Chester County, which adds a chop.

I do have one question about your criteria. Do non-contiguous chops from one district count as one or more (such as PA-13 in the map above)?

[muon2]

There is a school of thought that says one redistricting principle should be: In any county greater than the population for a whole district there should be a number of districts completely within the county equal to the population of the county divided by the quota for one district, rounded down to the nearest whole number. In PA that would require 2 CDs in wholly in Philly, 1 wholly in Montco, and 1 wholly in Allegheny.

We debated the merits of this principle on threads on this board back in 2012-13. In the end the majority view here was that a count of the total number of chops was a more important principle than considering how the fragments of the chops nested within counties. I shared that view in part from my experience in the 2011 OH Redistricting Competition, which had nesting requirements for legislative districts and rules that created a preference for wholly-contained districts in the congressional plan. I thought it created unneeded skews to other measures of the plan.

I'm not sure I necessarily agree, but I admit I haven't fully explored the issue. I have always considered it a high priority when I've drawn maps. For PA, I have always followed the requirements you noted of that criteria. For OH, that would mean one district each entirely contained within each of Cuyahoga, Franklin, and Hamilton Counties. I don't really see a strong argument against having such a standard.

In this case, however, the two criteria are not in conflict (unless chopping a county an additional time violates certain criteria). In the map we're discussing, the districts basically move counter-clockwise. PA-01 moves out of Delco, eliminating the chop of that county. And ultimately, through a number of changes, PA-06 moves into Chester County, which adds a chop.

I do have one question about your criteria. Do non-contiguous chops from one district count as one or more (such as PA-13 in the map above)?

Here's the definitions worked out on the subject of chops (edited to reflect current use). Chops involving more than one fragment of a district are still just a chop. However, chops involving multiple fragments will typically have higher erosity, as each fragment counts separately for connections. The creates a small disincentive for fragmented chops, but that fragmentation might preserve towns or wards from additional chops.

Definition: Chop. A single chop is the division of a geographic unit between two districts. A second chop divides the unit between three districts. In general the number of chops is equal to the number of districts in that unit less one.

Definition: Chop size. In units with a single chop, the size of a chop is the population of the smaller district within the unit. For districts with more than one chop, chop sizes are measured in order from the smallest populated district in the unit up to but not including the district with the largest population in the unit.

Definition: Macrochop. A macrochop is one or more chops in a county that has a total size in excess of 5.0% of the quota. When a macrochop of a county occurs, the subunits of the county must be considered as if they were units as well. Note that macrochops may only apply to counties with a population of more than 10% of the quota, and must apply to counties with more than 105% of the quota.

Item 10: CHOP measures the integrity of geographic units in a plan. The CHOP score is the total of all county chops. In counties with a macrochop, chops of county subunits are added to the CHOP score, however VTDs that span county subdivisions do not increase the CHOP score.

[AustralianSwingVoter]

For a plan with N districts, there should not be more than N-1 county chops without a clearly definable reason. In a state like PA with lots of well defined cities, towns and Philly wards (identified by the names of the vote districts in DRA) there is no reason other than trying for exact population equality to chop any of them. Doing so divides a community of interest (less so with some of the wards). There are enough of those county subdivisions that it should always be possible to get within a relatively small deviation, probably under 1000 and certainly less than 0.5%.

The five Philly area counties plus Berks and Lancaster are a near perfect fit for 7 CDs with 2010 data. There should be no more than 6 chops in those counties, and this plan does that (3 chops in Philly, 1 each in Montco, Delco, and Chester. I don't know if towns and wards were preserved whole though, but I presume some minor adjustments could be made to respect those lines.

The county splits out west are a different matter. I know ASV said he thought the communities of interest are more important, but I'm not how that applies there. The western boundary of Cambria and Somerset counties is a significant mountain ridge that is largely protected by state forests. It seems that this plan tries to use the next, lower ridge to the west as the line separating communities of interest, but that doesn't comport with the actually lifestyle patterns in that part of the state from my visits. Those county lines in this case do a pretty good job of marking the separation between regions.

I think that PA-01 is a violation of any fair and reasonable map. Philadelphia has the population for at least two districts. I think that should require, in any fair map, that the city/county should have two districts within its boundaries. That does mean an additional chop of Chester, however I believe the preceding criteria should take precedence. And furthermore, I think the other problem with SEPA in that map is that PA-13 takes in two non-contiguous parts of Philadelphia.

Like I said, I don't think it's an overall unreasonable map apart from what I mentioned above. It just needs some cleaning up in terms of county splits. I would work on it myself, but I don't want to start from scratch. To start, I would swap numbering between PA-11 and PA-17 and I would make the new PA-11 a Lackawanna/Luzerne/Monroe district.

There is a school of thought that says one redistricting principle should be: In any county greater than the population for a whole district there should be a number of districts completely within the county equal to the population of the county divided by the quota for one district, rounded down to the nearest whole number. In PA that would require 2 CDs in wholly in Philly, 1 wholly in Montco, and 1 wholly in Allegheny.

We debated the merits of this principle on threads on this board back in 2012-13. In the end the majority view here was that a count of the total number of chops was a more important principle than considering how the fragments of the chops nested within counties. I shared that view in part from my experience in the 2011 OH Redistricting Competition, which had nesting requirements for legislative districts and rules that created a preference for wholly-contained districts in the congressional plan. I thought it created unneeded skews to other measures of the plan.

PA-1 and 2 could be entirely within Philly County, however I should have made it clearer that the arrangement exists solely to allow for 2 Black Majority congressional districts in Philly.

The 2010 Census had 665K blacks (including Hispanic blacks) in the city of Philadelphia. The 2010 Census set a quota of 706K per CD. The black population in Philly isn't large enough to be the majority in 2 CDs.

That is why the 1st congressional district ventures into Delaware County, so that, on DRA figures:

District 1 D+36.23 - 86.0 - 13.5 - 50.5 African American
District 2 D+40.09 - 89.4 - 10.2 - 50.1 African American

[muon2]

For a plan with N districts, there should not be more than N-1 county chops without a clearly definable reason. In a state like PA with lots of well defined cities, towns and Philly wards (identified by the names of the vote districts in DRA) there is no reason other than trying for exact population equality to chop any of them. Doing so divides a community of interest (less so with some of the wards). There are enough of those county subdivisions that it should always be possible to get within a relatively small deviation, probably under 1000 and certainly less than 0.5%.

The five Philly area counties plus Berks and Lancaster are a near perfect fit for 7 CDs with 2010 data. There should be no more than 6 chops in those counties, and this plan does that (3 chops in Philly, 1 each in Montco, Delco, and Chester. I don't know if towns and wards were preserved whole though, but I presume some minor adjustments could be made to respect those lines.

The county splits out west are a different matter. I know ASV said he thought the communities of interest are more important, but I'm not how that applies there. The western boundary of Cambria and Somerset counties is a significant mountain ridge that is largely protected by state forests. It seems that this plan tries to use the next, lower ridge to the west as the line separating communities of interest, but that doesn't comport with the actually lifestyle patterns in that part of the state from my visits. Those county lines in this case do a pretty good job of marking the separation between regions.

I think that PA-01 is a violation of any fair and reasonable map. Philadelphia has the population for at least two districts. I think that should require, in any fair map, that the city/county should have two districts within its boundaries. That does mean an additional chop of Chester, however I believe the preceding criteria should take precedence. And furthermore, I think the other problem with SEPA in that map is that PA-13 takes in two non-contiguous parts of Philadelphia.

Like I said, I don't think it's an overall unreasonable map apart from what I mentioned above. It just needs some cleaning up in terms of county splits. I would work on it myself, but I don't want to start from scratch. To start, I would swap numbering between PA-11 and PA-17 and I would make the new PA-11 a Lackawanna/Luzerne/Monroe district.

There is a school of thought that says one redistricting principle should be: In any county greater than the population for a whole district there should be a number of districts completely within the county equal to the population of the county divided by the quota for one district, rounded down to the nearest whole number. In PA that would require 2 CDs in wholly in Philly, 1 wholly in Montco, and 1 wholly in Allegheny.

We debated the merits of this principle on threads on this board back in 2012-13. In the end the majority view here was that a count of the total number of chops was a more important principle than considering how the fragments of the chops nested within counties. I shared that view in part from my experience in the 2011 OH Redistricting Competition, which had nesting requirements for legislative districts and rules that created a preference for wholly-contained districts in the congressional plan. I thought it created unneeded skews to other measures of the plan.

PA-1 and 2 could be entirely within Philly County, however I should have made it clearer that the arrangement exists solely to allow for 2 Black Majority congressional districts in Philly.

The 2010 Census had 665K blacks (including Hispanic blacks) in the city of Philadelphia. The 2010 Census set a quota of 706K per CD. The black population in Philly isn't large enough to be the majority in 2 CDs.

That is why the 1st congressional district ventures into Delaware County, so that, on DRA figures:

District 1 D+36.23 - 86.0 - 13.5 - 50.5 African American
District 2 D+40.09 - 89.4 - 10.2 - 50.1 African American

Is that black population or black VAP? The latter is what counts in determining if it is majority black.

[AustralianSwingVoter]

For a plan with N districts, there should not be more than N-1 county chops without a clearly definable reason. In a state like PA with lots of well defined cities, towns and Philly wards (identified by the names of the vote districts in DRA) there is no reason other than trying for exact population equality to chop any of them. Doing so divides a community of interest (less so with some of the wards). There are enough of those county subdivisions that it should always be possible to get within a relatively small deviation, probably under 1000 and certainly less than 0.5%.

The five Philly area counties plus Berks and Lancaster are a near perfect fit for 7 CDs with 2010 data. There should be no more than 6 chops in those counties, and this plan does that (3 chops in Philly, 1 each in Montco, Delco, and Chester. I don't know if towns and wards were preserved whole though, but I presume some minor adjustments could be made to respect those lines.

The county splits out west are a different matter. I know ASV said he thought the communities of interest are more important, but I'm not how that applies there. The western boundary of Cambria and Somerset counties is a significant mountain ridge that is largely protected by state forests. It seems that this plan tries to use the next, lower ridge to the west as the line separating communities of interest, but that doesn't comport with the actually lifestyle patterns in that part of the state from my visits. Those county lines in this case do a pretty good job of marking the separation between regions.

I think that PA-01 is a violation of any fair and reasonable map. Philadelphia has the population for at least two districts. I think that should require, in any fair map, that the city/county should have two districts within its boundaries. That does mean an additional chop of Chester, however I believe the preceding criteria should take precedence. And furthermore, I think the other problem with SEPA in that map is that PA-13 takes in two non-contiguous parts of Philadelphia.

Like I said, I don't think it's an overall unreasonable map apart from what I mentioned above. It just needs some cleaning up in terms of county splits. I would work on it myself, but I don't want to start from scratch. To start, I would swap numbering between PA-11 and PA-17 and I would make the new PA-11 a Lackawanna/Luzerne/Monroe district.

There is a school of thought that says one redistricting principle should be: In any county greater than the population for a whole district there should be a number of districts completely within the county equal to the population of the county divided by the quota for one district, rounded down to the nearest whole number. In PA that would require 2 CDs in wholly in Philly, 1 wholly in Montco, and 1 wholly in Allegheny.

We debated the merits of this principle on threads on this board back in 2012-13. In the end the majority view here was that a count of the total number of chops was a more important principle than considering how the fragments of the chops nested within counties. I shared that view in part from my experience in the 2011 OH Redistricting Competition, which had nesting requirements for legislative districts and rules that created a preference for wholly-contained districts in the congressional plan. I thought it created unneeded skews to other measures of the plan.

PA-1 and 2 could be entirely within Philly County, however I should have made it clearer that the arrangement exists solely to allow for 2 Black Majority congressional districts in Philly.

The 2010 Census had 665K blacks (including Hispanic blacks) in the city of Philadelphia. The 2010 Census set a quota of 706K per CD. The black population in Philly isn't large enough to be the majority in 2 CDs.

That is why the 1st congressional district ventures into Delaware County, so that, on DRA figures:

District 1 D+36.23 - 86.0 - 13.5 - 50.5 African American
District 2 D+40.09 - 89.4 - 10.2 - 50.1 African American

Is that black population or black VAP? The latter is what counts in determining if it is majority black.

It's whatever DRA gives as African-American

[muon2]

For a plan with N districts, there should not be more than N-1 county chops without a clearly definable reason. In a state like PA with lots of well defined cities, towns and Philly wards (identified by the names of the vote districts in DRA) there is no reason other than trying for exact population equality to chop any of them. Doing so divides a community of interest (less so with some of the wards). There are enough of those county subdivisions that it should always be possible to get within a relatively small deviation, probably under 1000 and certainly less than 0.5%.

The five Philly area counties plus Berks and Lancaster are a near perfect fit for 7 CDs with 2010 data. There should be no more than 6 chops in those counties, and this plan does that (3 chops in Philly, 1 each in Montco, Delco, and Chester. I don't know if towns and wards were preserved whole though, but I presume some minor adjustments could be made to respect those lines.

The county splits out west are a different matter. I know ASV said he thought the communities of interest are more important, but I'm not how that applies there. The western boundary of Cambria and Somerset counties is a significant mountain ridge that is largely protected by state forests. It seems that this plan tries to use the next, lower ridge to the west as the line separating communities of interest, but that doesn't comport with the actually lifestyle patterns in that part of the state from my visits. Those county lines in this case do a pretty good job of marking the separation between regions.

I think that PA-01 is a violation of any fair and reasonable map. Philadelphia has the population for at least two districts. I think that should require, in any fair map, that the city/county should have two districts within its boundaries. That does mean an additional chop of Chester, however I believe the preceding criteria should take precedence. And furthermore, I think the other problem with SEPA in that map is that PA-13 takes in two non-contiguous parts of Philadelphia.

Like I said, I don't think it's an overall unreasonable map apart from what I mentioned above. It just needs some cleaning up in terms of county splits. I would work on it myself, but I don't want to start from scratch. To start, I would swap numbering between PA-11 and PA-17 and I would make the new PA-11 a Lackawanna/Luzerne/Monroe district.

There is a school of thought that says one redistricting principle should be: In any county greater than the population for a whole district there should be a number of districts completely within the county equal to the population of the county divided by the quota for one district, rounded down to the nearest whole number. In PA that would require 2 CDs in wholly in Philly, 1 wholly in Montco, and 1 wholly in Allegheny.

We debated the merits of this principle on threads on this board back in 2012-13. In the end the majority view here was that a count of the total number of chops was a more important principle than considering how the fragments of the chops nested within counties. I shared that view in part from my experience in the 2011 OH Redistricting Competition, which had nesting requirements for legislative districts and rules that created a preference for wholly-contained districts in the congressional plan. I thought it created unneeded skews to other measures of the plan.

PA-1 and 2 could be entirely within Philly County, however I should have made it clearer that the arrangement exists solely to allow for 2 Black Majority congressional districts in Philly.

The 2010 Census had 665K blacks (including Hispanic blacks) in the city of Philadelphia. The 2010 Census set a quota of 706K per CD. The black population in Philly isn't large enough to be the majority in 2 CDs.

That is why the 1st congressional district ventures into Delaware County, so that, on DRA figures:

District 1 D+36.23 - 86.0 - 13.5 - 50.5 African American
District 2 D+40.09 - 89.4 - 10.2 - 50.1 African American

Is that black population or black VAP? The latter is what counts in determining if it is majority black.

It's whatever DRA gives as African-American

It gives two different boxes for demographics. The upper box is for the whole population. Back around 2010, I pointed out to DRA that the voting age population (VAP) is what the courts look at to determine the minority strength, and they added a second box below the first. It's the percentages in the second box that matter.

[AustralianSwingVoter]

For a plan with N districts, there should not be more than N-1 county chops without a clearly definable reason. In a state like PA with lots of well defined cities, towns and Philly wards (identified by the names of the vote districts in DRA) there is no reason other than trying for exact population equality to chop any of them. Doing so divides a community of interest (less so with some of the wards). There are enough of those county subdivisions that it should always be possible to get within a relatively small deviation, probably under 1000 and certainly less than 0.5%.

The five Philly area counties plus Berks and Lancaster are a near perfect fit for 7 CDs with 2010 data. There should be no more than 6 chops in those counties, and this plan does that (3 chops in Philly, 1 each in Montco, Delco, and Chester. I don't know if towns and wards were preserved whole though, but I presume some minor adjustments could be made to respect those lines.

The county splits out west are a different matter. I know ASV said he thought the communities of interest are more important, but I'm not how that applies there. The western boundary of Cambria and Somerset counties is a significant mountain ridge that is largely protected by state forests. It seems that this plan tries to use the next, lower ridge to the west as the line separating communities of interest, but that doesn't comport with the actually lifestyle patterns in that part of the state from my visits. Those county lines in this case do a pretty good job of marking the separation between regions.

I think that PA-01 is a violation of any fair and reasonable map. Philadelphia has the population for at least two districts. I think that should require, in any fair map, that the city/county should have two districts within its boundaries. That does mean an additional chop of Chester, however I believe the preceding criteria should take precedence. And furthermore, I think the other problem with SEPA in that map is that PA-13 takes in two non-contiguous parts of Philadelphia.

Like I said, I don't think it's an overall unreasonable map apart from what I mentioned above. It just needs some cleaning up in terms of county splits. I would work on it myself, but I don't want to start from scratch. To start, I would swap numbering between PA-11 and PA-17 and I would make the new PA-11 a Lackawanna/Luzerne/Monroe district.

There is a school of thought that says one redistricting principle should be: In any county greater than the population for a whole district there should be a number of districts completely within the county equal to the population of the county divided by the quota for one district, rounded down to the nearest whole number. In PA that would require 2 CDs in wholly in Philly, 1 wholly in Montco, and 1 wholly in Allegheny.

We debated the merits of this principle on threads on this board back in 2012-13. In the end the majority view here was that a count of the total number of chops was a more important principle than considering how the fragments of the chops nested within counties. I shared that view in part from my experience in the 2011 OH Redistricting Competition, which had nesting requirements for legislative districts and rules that created a preference for wholly-contained districts in the congressional plan. I thought it created unneeded skews to other measures of the plan.

PA-1 and 2 could be entirely within Philly County, however I should have made it clearer that the arrangement exists solely to allow for 2 Black Majority congressional districts in Philly.

The 2010 Census had 665K blacks (including Hispanic blacks) in the city of Philadelphia. The 2010 Census set a quota of 706K per CD. The black population in Philly isn't large enough to be the majority in 2 CDs.

That is why the 1st congressional district ventures into Delaware County, so that, on DRA figures:

District 1 D+36.23 - 86.0 - 13.5 - 50.5 African American
District 2 D+40.09 - 89.4 - 10.2 - 50.1 African American

Is that black population or black VAP? The latter is what counts in determining if it is majority black.

It's whatever DRA gives as African-American

It gives two different boxes for demographics. The upper box is for the whole population. Back around 2010, I pointed out to DRA that the voting age population (VAP) is what the courts look at to determine the minority strength, and they added a second box below the first. It's the percentages in the second box that matter.

I always tick all the don't show boxes, after looking just now it seems that I have been ticking the box, however as DRA already crashes my computer quite frequently I don't want to have to be on my knees screaming to the heavens "NOOOOO, WHYYYYY" any more than I already have to. Remember, I'm doing it on a MacBook Air with 50 chrome tabs always open. I've already had to have my battery replaced twice when the first should be good until 2019.

[Torie]

Back in 2013 I looked at PA using DRA as the muon rules were first being fleshed out. With help from Torie, traininthedistance, and jimrtex, I came up with a balanced neutral plan. I couldn't find my drf file from back then, so I reconstructed it with a couple of tweaks to reflect the current version of the rules.



Chester is the only macrochopped county smaller than a CD, and only three other small counties have regular chops. No city/borough/township is chopped except Philly, and no ward within Philly is chopped. Obama won 11 of the 18 CDs in 2008. DRA population deviations and current PVIs for the CDs are:

CD 1: (-42) D+24
CD 2: (-497) D+39; BVAP 52.6%
CD 3: (+180) R+8
CD 4: (-1808) R+17
CD 5: (+1704) R+15
CD 6: (-691) R+3
CD 7: (-616) D+8
CD 8: (+1566) R+1
CD 9: (+1078) R+20
CD 10: (-1173) R+17
CD 11: (-491) D+0
CD 12: (+1919) R+13
CD 13: (-636) D+17
CD 14: (+921) D+10
CD 15: (-2359) R+0
CD 16: (+963) R+9
CD 17: (-1047) R+9
CD 18: (+1006) R+3

This might give some sense as to what a new neutral map might produce.

Edit: fixed the PVIs by using old voting districts

Muon2’s map is drawn to minimize county chops, but must have been crafted before his rules included pack (fewer CD’s located wholly within the boundaries of a metro area than the maximum possible) and cover (more CD’s wholly or partially located within the boundaries of a metro area than the minimum possible) penalties with respect to multi-county metro areas (as defined by the US census, except that more rural counties included therein are excised per an algorithm fashioned by the most indefatigable and creative Jimrtex).    

His map as compared to my cover and pack penalty free effort below (the multi county metro areas as defined by Jimrtex are outlined out on my map) has cover and pack penalties for the Philly and Allentown metro areas (with the ones for Allentown easily avoided by chopping into Carbon rather than Lehigh County), and a cover penalty for the Pittsburg metro area.  By tri-chopping Alleghany County, he also generates an extra macro chop, which may or may not generate more erosity penalty points in that county than my map does).  Given his monomaniacal focus on minimizing county chops, he does however have one fewer county chop than the map below. ☺

The BVAP for PA-02 is 48.4% by the way in the map below.  It also contains no municipality chops (or ward chops in Philly), other than the one that is unavoidable (i.e. Philadelphia, which really does not count since its lines are co-terminous with the county lines).

[President Punxsutawney Phil]

Muon2’s map is drawn to minimize county chops, but must have been crafted before his rules included pack (fewer CD’s located wholly within the boundaries of a metro area than the maximum possible) and cover (more CD’s wholly or partially located within the boundaries of a metro area than the minimum possible) penalties with respect to multi-county metro areas (as defined by the US census, except that more rural counties included therein are excised per an algorithm fashioned by the most indefatigable and creative Jimrtex).    

His map as compared to my cover and pack penalty free effort below (the multi county metro areas as defined by Jimrtex are outlined out on my map) has cover and pack penalties for the Philly and Allentown metro areas (with the ones for Allentown easily avoided by chopping into Carbon rather than Lehigh County), and a cover penalty for the Pittsburg metro area.  By tri-chopping Alleghany County, he also generates an extra macro chop, which may or may not generate more erosity penalty points in that county than my map does).  Given his monomaniacal focus on minimizing county chops, he does however have one fewer county chop than the map below. ☺

The BVAP for PA-02 is 48.4% by the way in the map below.  It also contains no municipality chops (or ward chops in Philly), other than the one that is unavoidable (i.e. Philadelphia, which really does not count since its lines are co-terminous with the county lines).

Just gotta say I love how clean this map is.
How did these seats vote?

[Torie]

Thank you. My guess at PVI relying in part on the Toomey numbers which I think are more indicative of party strength going forward than the Trump coalition, is that PA-01, 02, 07, 13 and 14 are Dem bastions, PA-17 has a Dem PVI of about 2, PA-08 is a swing seat with a Pub PVI of maybe 1 and quite stable overall, PA-06 and PA-15 both have a Pub PVI of about 2 (with PA-06 trending Dem, and PA-15 fairly stable overall), and  the other 9 seats are Pub bastions. After the 2020 census, one of the Pub bastion seats (i.e. PA-05) will disappear.

[politicallefty]

Here's the definitions worked out on the subject of chops (edited to reflect current use). Chops involving more than one fragment of a district are still just a chop. However, chops involving multiple fragments will typically have higher erosity, as each fragment counts separately for connections. The creates a small disincentive for fragmented chops, but that fragmentation might preserve towns or wards from additional chops.

Definition: Chop. A single chop is the division of a geographic unit between two districts. A second chop divides the unit between three districts. In general the number of chops is equal to the number of districts in that unit less one.

Definition: Chop size. In units with a single chop, the size of a chop is the population of the smaller district within the unit. For districts with more than one chop, chop sizes are measured in order from the smallest populated district in the unit up to but not including the district with the largest population in the unit.

Definition: Macrochop. A macrochop is one or more chops in a county that has a total size in excess of 5.0% of the quota. When a macrochop of a county occurs, the subunits of the county must be considered as if they were units as well. Note that macrochops may only apply to counties with a population of more than 10% of the quota, and must apply to counties with more than 105% of the quota.

Item 10: CHOP measures the integrity of geographic units in a plan. The CHOP score is the total of all county chops. In counties with a macrochop, chops of county subunits are added to the CHOP score, however VTDs that span county subdivisions do not increase the CHOP score.

Ugh, my first response died in a browser crash. I just have to say, for someone that places county integrity so high, I don't understand why you don't place the criteria I mentioned higher. If a county can support a certain number of districts within its boundaries, I think it should be required to do so. Philadelphia County should have two districts completely within its boundaries.

Thank you. My guess at PVI relying in part on the Toomey numbers which I think are more indicative of party strength going forward than the Trump coalition, is that PA-01, 02, 07, 13 and 14 are Dem bastions, PA-17 has a Dem PVI of about 2, PA-08 is a swing seat with a Pub PVI of maybe 1 and quite stable overall, PA-06 and PA-15 both have a Pub PVI of about 2 (with PA-06 trending Dem, and PA-15 fairly stable overall), and  the other 9 seats are Pub bastions. After the 2020 census, one of the Pub bastion seats (i.e. PA-05) will disappear.

I think SWPA could be drawn better. Attaching Butler County to the remainder of Allegheny seems like a Republican strategy. I think a more fair map would attach the remainder of Allegheny with Beaver County.

[muon2]

It has to do with how you count divisions of geographic units and what is the impact of a large county within its metro area. During the formulation of the definition of chop there were some you agreed with you. Even the OH competition used language that you'd like better (edited for clarity):

A fragment is a contiguous part of a district within a county that is not the entire county or the entire district. The Fragment score is the total count of all fragments.

During the competition I found that this had a defect in the way it scored small counties compared to large counties (those larger than a district). It had a discontinuity when a county was first chopped, such that small counties either had 0 or 2+ fragments, but never 1 fragment. However large counties could never have less than 1 fragment. This created opportunities to pack chops in the large counties.

FL used a different method of counting, and only counted the number of counties that had more than 1 district. This also served to force more fragments into the large counties.

One other problem with forcing the maximum districts into a county has to do with metro areas, and large counties are generally part of a multi-county metro area. Counties in a metro area tend to be larger than average for the state, and the lack of smaller counties make it harder to come up with county combinations that equal a whole number of districts. Forcing districts into a county compounds this problem and increases the likelihood that more chops are needed in the counties around the large central county. This is a bias in favor of the central county integrity at the expense of its neighbors.

My solution is to treat all counties exactly the same, regardless of their size. I do that by counting chops, not the pieces created by the chops.

[Torie]

Here's the definitions worked out on the subject of chops (edited to reflect current use). Chops involving more than one fragment of a district are still just a chop. However, chops involving multiple fragments will typically have higher erosity, as each fragment counts separately for connections. The creates a small disincentive for fragmented chops, but that fragmentation might preserve towns or wards from additional chops.

Definition: Chop. A single chop is the division of a geographic unit between two districts. A second chop divides the unit between three districts. In general the number of chops is equal to the number of districts in that unit less one.

Definition: Chop size. In units with a single chop, the size of a chop is the population of the smaller district within the unit. For districts with more than one chop, chop sizes are measured in order from the smallest populated district in the unit up to but not including the district with the largest population in the unit.

Definition: Macrochop. A macrochop is one or more chops in a county that has a total size in excess of 5.0% of the quota. When a macrochop of a county occurs, the subunits of the county must be considered as if they were units as well. Note that macrochops may only apply to counties with a population of more than 10% of the quota, and must apply to counties with more than 105% of the quota.

Item 10: CHOP measures the integrity of geographic units in a plan. The CHOP score is the total of all county chops. In counties with a macrochop, chops of county subunits are added to the CHOP score, however VTDs that span county subdivisions do not increase the CHOP score.

Ugh, my first response died in a browser crash. I just have to say, for someone that places county integrity so high, I don't understand why you don't place the criteria I mentioned higher. If a county can support a certain number of districts within its boundaries, I think it should be required to do so. Philadelphia County should have two districts completely within its boundaries.

Thank you. My guess at PVI relying in part on the Toomey numbers which I think are more indicative of party strength going forward than the Trump coalition, is that PA-01, 02, 07, 13 and 14 are Dem bastions, PA-17 has a Dem PVI of about 2, PA-08 is a swing seat with a Pub PVI of maybe 1 and quite stable overall, PA-06 and PA-15 both have a Pub PVI of about 2 (with PA-06 trending Dem, and PA-15 fairly stable overall), and  the other 9 seats are Pub bastions. After the 2020 census, one of the Pub bastion seats (i.e. PA-05) will disappear.

I think SWPA could be drawn better. Attaching Butler County to the remainder of Allegheny seems like a Republican strategy. I think a more fair map would attach the remainder of Allegheny with Beaver County.

Doing as you suggest would generate another county chop. That is the beauty of this system. Partisan figures are irrelevant. At the end of the process, one then has a series of high scoring maps (one usually will end up with more than one competitive map, because with more chops, one can in most cases reduce erosity), and one can certainly then have a system that rewards maps with a lower partisan "skew" as Muon2 puts it. So my Butler addition was not a partisan plot, but just how the cookie crumbled given the 2010 census numbers. After 2020, it may will be that northern Allegheny and Butler would get a divorce as it were. What you suggest would still leave you with a Pub CD in any event, unless things change a lot politically.