8 ms·

There is a simple, game theoretically optimal solution to gerrymandering: an iterative process of I cut, you choose. https://www.cmu.edu/news/stories/archives/

by freen 9y ago

There is a simple, game theoretically optimal solution to gerrymandering: an iterative process of I cut, you choose. https://www.cmu.edu/news/stories/archives/2017/november/i-cut-you-choose-cake-cutting-protocol-inspires-solution-to-gerrymandering.html https://www.cmu.edu/news/stories/archives/2017/november/i-cu...

ZeroGravitas 9y ago
This seems to assume a two-party system, which is probably pragmatic but maybe not totally optimal in a bigger sense.
- TheAdamAndChe 9y ago
  Well in the US, we have a two-party system, so we wouldn't exactly want to apply a solution that's optimal for a multi-party system.
  - alistairSH 9y ago
    We have a de facto two-party system because that's the outcome of a FPP voting system. Nowhere is the two party system codified and nowhere is it declared optimal or even desirable. Point being, optimizing districting to maintain a 2-party system may not be desirable, even if that's the system we've fallen into. We could change voting systems to introduce more viable parties (which has it's own problems - look at unstable governments in Europe based on oddball alliances).
    - vidarh 9y ago
      > (which has it's own problems - look at unstable governments in Europe based on oddball alliances). That's not a problem, that's a feature. It ensures the parties need to learn to cooperate and compromise to get things through when voters are not in firm agreement. As a result you get continuity: It's rare to get the kind of drastic shifts that you get in the US when the balance shifts between the Republicans and Democrats, because it is rare for a single party to get an absolute majority, and so alliances shift with voting patterns, and the negotiated compromises tends to have to reflect a wider range of interests or not get passed. A lot of places this leads to a tradition of broad compromises to ensure lasting reforms that won't just get undone by the next government. So while the specific governments may not sit as tightly, I'd argue it tends to lead to a lot more stability in government direction.
      - willyt 9y ago
        Exactly. Successive governments in the UK waste vast amounts on money on stuff like health service reform, which get unpicked by the next government. It is deeply stupid the amount of money we in the UK spent on brand new nursery schools that were built 2000-2010 and then abandoned after 2010.
      - mamon 9y ago
        There's also an issue with that system: it gives a ruling party an easy excuse for not keeping their promises to their voters. You can always say: "We tried, but we didn't have a majority and our allied party was against that".I can't count how many times I heard that being said in my country. Also, there's another bad consequence: In two party system when you lose the elections you really loose: other party takes the whole prize, and for you there's really nothing to do for the next four years. In multi party system even if you finish the elections on 2nd or 3rd place you may still end up joining the ruling coalition of parties, just maybe with somewhat weaker position. Basically European system shifts focus of political parties from making deals with their voters to making deals with other parties.
        dragonwriter 9y ago
        > There's also an issue with that system: it gives a ruling party an easy excuse for not keeping their promises to their voters. The US two-parties-that-are-obviously-fractious-coalitions plus separation of powers system provides far more of those for any elected leader (because it's not a parliamentary system and lacks real mechanisms for party discipline, even a party with control of both political branches and the judiciary isn't analogous to a parliamentary-system ruling party with an outright, non-coalition majority, and isn't held accountable the way those can be. Keeping separation of powers and adopting a more proportional system for the House of Reps, even straight party list (which would require Constitutional change), or state level party list or STV with or without some level of districting (which may or may not require Constitutional change) would not meaningfully add to the excuses for failure to deliver on promises. In fact, systems with greater proportionality in legislative elections produce higher satisfaction with government, which should be unsurprising: electing a government that's views actually align with those of the population results in government policy more aligned with public preferences. Which, after all, is the whole premise of representative democracy.
    - lurr 9y ago
      > look at unstable governments in Europe based on oddball alliances vs hammering through legislation with zero bipartisanship. Which is actually a problem in parliamentary systems that end up with majorities. These coalition governments are a feature, not a bug.
    - dragonwriter 9y ago
      > We could change voting systems to introduce more viable parties (which has it's own problems - look at unstable governments in Europe based on oddball alliances). Those systems aren't really unstable, they just formalize things that go on behind the scenes in the US system where the major parties are actually internally diverse coalition with competitive factions.
- oconnor663 9y ago
  Is there a way to cut a cake between 3 people with this sort of approach? If there's not a way in general, could there be a way with the added assumption that cooperation to screw the 3rd person would be detectable and publicly shamed enough to disincentivize it?
  - ZeroGravitas 9y ago
    Apparently there is a way, but it's complicated and probably doesn't translate from cake to maps (you don't end up with neat slices, but rather a collection of different sized pieces): https://www.quantamagazine.org/new-algorithm-solves-cake-cutting-problem-20161006/ https://www.quantamagazine.org/new-algorithm-solves-cake-cut... And it's not clear if one of the cake cutters could sacrifice their own slice to benefit one of the others (in return for a bribe).
    - mc32 9y ago
      One could almost be certain there would be some underhanded quid pro quo with this situation.
  - deleted 9y ago
    [deleted]
  - jeffwass 9y ago
    Yes, “envy-free” cake cutting. https://en.m.wikipedia.org/wiki/Envy-free_cake-cutting https://en.m.wikipedia.org/wiki/Envy-free_cake-cutting
    - oconnor663 9y ago
      Ha, the "Robertson–Webb rotating-knife procedure" sounds like a move from Kill Bill.
  - QuotedForTruth 9y ago
    There is a general solution. Im not sure how you could apply it to creating districts for voting though. https://www.youtube.com/watch?v=kaMKInkV7Vs https://www.youtube.com/watch?v=kaMKInkV7Vs
acdanger 9y ago
This solution traces its origins back to the Book of Genesis. Perhaps that would help the case for implementing it in the USA? https://en.wikipedia.org/wiki/Divide_and_choose#History https://en.wikipedia.org/wiki/Divide_and_choose#History
balthasar 9y ago
This is so clever and effective that I guarantee it will never gain traction.
bzbarsky 9y ago
This solves one aspect of the gerrymandering problem. The problem is that there are multiple aspects. As one example, people want to both have majority-minority districts and avoid situations in which "specific populations of voters" (to quote the article) are concentrated into a district. These goals are often opposed to each other, especially when the minorities involved skew toward one of the two parties under consideration. So it's quite possible for a redistricting plan using the "I cut, you choose" process to end up falling afoul of Section 2 of the Voting Rights Act by diluting the voting strength of a minority...
- koheripbal 9y ago
  More generally, the issue is that it solidifies control to the two political parties participating in the "I cut you choose" game, which are both incentivized to marginalize any 3rd party. I wonder if the game can be fairly expanded to X number of parties?
  - bzbarsky 9y ago
    3rd parties are already so screwed, I don't even know where to start fixing the problems. For example, last I checked in Illinois third-party candidates needed _way_ more petition signatures to even get on a ballot than Republican or Democratic ones (though the legislation is careful to not call out the Republican or Democratic parties by name; it's written in terms of vote share in the previous election). That sort of thing is all over the place. As a mathematical exercise, trying to extend the game to more than 2 parties is interesting, for sure. Real-world relevance is unclear, unfortunately.
    - tripzilch 9y ago
      But if you're not even going to pretend 3rd parties (and 4th, 5th, etc) are even a remote possibility, you may as well give up pretending your democracy actually has the sort of good qualities that makes people prefer it over other types of government... (a hair's breadth away from calling it "not a democracy" because technically you still got to choose Kang over Kodos)
deleted 9y ago
[deleted]
0xWilliam 9y ago
But none of this matters because less then 50% of people in america even care to vote and no its not because drivers licenses or gerrymandering.

by freen 9y ago

ZeroGravitas 9y ago

This seems to assume a two-party system, which is probably pragmatic but maybe not totally optimal in a bigger sense.

TheAdamAndChe 9y ago
Well in the US, we have a two-party system, so we wouldn't exactly want to apply a solution that's optimal for a multi-party system.
- alistairSH 9y ago
  We have a de facto two-party system because that's the outcome of a FPP voting system. Nowhere is the two party system codified and nowhere is it declared optimal or even desirable. Point being, optimizing districting to maintain a 2-party system may not be desirable, even if that's the system we've fallen into. We could change voting systems to introduce more viable parties (which has it's own problems - look at unstable governments in Europe based on oddball alliances).
  - vidarh 9y ago
    > (which has it's own problems - look at unstable governments in Europe based on oddball alliances). That's not a problem, that's a feature. It ensures the parties need to learn to cooperate and compromise to get things through when voters are not in firm agreement. As a result you get continuity: It's rare to get the kind of drastic shifts that you get in the US when the balance shifts between the Republicans and Democrats, because it is rare for a single party to get an absolute majority, and so alliances shift with voting patterns, and the negotiated compromises tends to have to reflect a wider range of interests or not get passed. A lot of places this leads to a tradition of broad compromises to ensure lasting reforms that won't just get undone by the next government. So while the specific governments may not sit as tightly, I'd argue it tends to lead to a lot more stability in government direction.
    - willyt 9y ago
      Exactly. Successive governments in the UK waste vast amounts on money on stuff like health service reform, which get unpicked by the next government. It is deeply stupid the amount of money we in the UK spent on brand new nursery schools that were built 2000-2010 and then abandoned after 2010.
    - mamon 9y ago
      There's also an issue with that system: it gives a ruling party an easy excuse for not keeping their promises to their voters. You can always say: "We tried, but we didn't have a majority and our allied party was against that".I can't count how many times I heard that being said in my country. Also, there's another bad consequence: In two party system when you lose the elections you really loose: other party takes the whole prize, and for you there's really nothing to do for the next four years. In multi party system even if you finish the elections on 2nd or 3rd place you may still end up joining the ruling coalition of parties, just maybe with somewhat weaker position. Basically European system shifts focus of political parties from making deals with their voters to making deals with other parties.
      - dragonwriter 9y ago
        > There's also an issue with that system: it gives a ruling party an easy excuse for not keeping their promises to their voters. The US two-parties-that-are-obviously-fractious-coalitions plus separation of powers system provides far more of those for any elected leader (because it's not a parliamentary system and lacks real mechanisms for party discipline, even a party with control of both political branches and the judiciary isn't analogous to a parliamentary-system ruling party with an outright, non-coalition majority, and isn't held accountable the way those can be. Keeping separation of powers and adopting a more proportional system for the House of Reps, even straight party list (which would require Constitutional change), or state level party list or STV with or without some level of districting (which may or may not require Constitutional change) would not meaningfully add to the excuses for failure to deliver on promises. In fact, systems with greater proportionality in legislative elections produce higher satisfaction with government, which should be unsurprising: electing a government that's views actually align with those of the population results in government policy more aligned with public preferences. Which, after all, is the whole premise of representative democracy.
  - lurr 9y ago
    > look at unstable governments in Europe based on oddball alliances vs hammering through legislation with zero bipartisanship. Which is actually a problem in parliamentary systems that end up with majorities. These coalition governments are a feature, not a bug.
  - dragonwriter 9y ago
    > We could change voting systems to introduce more viable parties (which has it's own problems - look at unstable governments in Europe based on oddball alliances). Those systems aren't really unstable, they just formalize things that go on behind the scenes in the US system where the major parties are actually internally diverse coalition with competitive factions.
oconnor663 9y ago
Is there a way to cut a cake between 3 people with this sort of approach? If there's not a way in general, could there be a way with the added assumption that cooperation to screw the 3rd person would be detectable and publicly shamed enough to disincentivize it?
- ZeroGravitas 9y ago
  Apparently there is a way, but it's complicated and probably doesn't translate from cake to maps (you don't end up with neat slices, but rather a collection of different sized pieces): https://www.quantamagazine.org/new-algorithm-solves-cake-cutting-problem-20161006/ https://www.quantamagazine.org/new-algorithm-solves-cake-cut... And it's not clear if one of the cake cutters could sacrifice their own slice to benefit one of the others (in return for a bribe).
  - mc32 9y ago
    One could almost be certain there would be some underhanded quid pro quo with this situation.
- deleted 9y ago
  [deleted]
- jeffwass 9y ago
  Yes, “envy-free” cake cutting. https://en.m.wikipedia.org/wiki/Envy-free_cake-cutting https://en.m.wikipedia.org/wiki/Envy-free_cake-cutting
  - oconnor663 9y ago
    Ha, the "Robertson–Webb rotating-knife procedure" sounds like a move from Kill Bill.
- QuotedForTruth 9y ago
  There is a general solution. Im not sure how you could apply it to creating districts for voting though. https://www.youtube.com/watch?v=kaMKInkV7Vs https://www.youtube.com/watch?v=kaMKInkV7Vs

acdanger 9y ago

This solution traces its origins back to the Book of Genesis. Perhaps that would help the case for implementing it in the USA? https://en.wikipedia.org/wiki/Divide_and_choose#History https://en.wikipedia.org/wiki/Divide_and_choose#History

balthasar 9y ago

This is so clever and effective that I guarantee it will never gain traction.

bzbarsky 9y ago

This solves one aspect of the gerrymandering problem. The problem is that there are multiple aspects. As one example, people want to both have majority-minority districts and avoid situations in which "specific populations of voters" (to quote the article) are concentrated into a district. These goals are often opposed to each other, especially when the minorities involved skew toward one of the two parties under consideration. So it's quite possible for a redistricting plan using the "I cut, you choose" process to end up falling afoul of Section 2 of the Voting Rights Act by diluting the voting strength of a minority...

koheripbal 9y ago
More generally, the issue is that it solidifies control to the two political parties participating in the "I cut you choose" game, which are both incentivized to marginalize any 3rd party. I wonder if the game can be fairly expanded to X number of parties?
- bzbarsky 9y ago
  3rd parties are already so screwed, I don't even know where to start fixing the problems. For example, last I checked in Illinois third-party candidates needed _way_ more petition signatures to even get on a ballot than Republican or Democratic ones (though the legislation is careful to not call out the Republican or Democratic parties by name; it's written in terms of vote share in the previous election). That sort of thing is all over the place. As a mathematical exercise, trying to extend the game to more than 2 parties is interesting, for sure. Real-world relevance is unclear, unfortunately.
  - tripzilch 9y ago
    But if you're not even going to pretend 3rd parties (and 4th, 5th, etc) are even a remote possibility, you may as well give up pretending your democracy actually has the sort of good qualities that makes people prefer it over other types of government... (a hair's breadth away from calling it "not a democracy" because technically you still got to choose Kang over Kodos)

deleted 9y ago

[deleted]

0xWilliam 9y ago

But none of this matters because less then 50% of people in america even care to vote and no its not because drivers licenses or gerrymandering.