> How do you get proportional representation with single-member districts without involving party lists somehow (as in e.g. MMP)?
It's hard if you keep single-member districts, though there are possibilitie: (e.g., assign seats to parties based on share first-preference votes across all districts, with all the same handling of minimum thresholds, etc, you would apply in party list proportional, and then elect specific candidates from the by-district elections as follows:
- If a parties total number of allocated seats is equal to the number of candidates they have remaining in districts where no candidate has been elected, elect all of those candidates.
- Otherwise, elect the candidate from the party whose currently-elected # of candidates is the smallest fraction of their allocated seats (breaking ties in favor of the largest absolute deficit) who has the greatest share of the vote in the district in which they competed.
- Repeat until all allocated seats are filled.
Voilà: all the partisan proportionality of party-list proportional, with candidates elected from single-member districts, with candidate centered voting, and no party lists.
I think practically STV or a similar system in small multimember districts (about 5 members per district) is probably a better balance of proportionality and individual candidate accountability (and results in more people having a candidate that is both local and politically acceptable than most other systems), and STV of course can scale to any level of proportionality at the expense of greater number of candidates and larger districts.
Party lists provide an easy route to partisan proportionality but eliminate direct accountability to the general electorate of individual representatives. Ideally, I think, you want both proportionality and individual accountability to the general electorate.
I think direct accountability is overrated. Not to say that it shouldn't be there, but I don't think it's important enough that the electoral system should be fixated on it as the primary goal. For example, in US today, despite single-member districts (which put it as the cornerstone), party politics dominate in practice.
I think MMP is a reasonable compromise system between direct accountability and regional representation on one hand, and proportional representation of national politics on the other - each district still gets a direct representative (or several; I'm not opposed to multimember districts in general), but party lists are used to keep the overall balance of power in line with the national vote.
The risk with the system that you describe is that it can still skew results substantially. For example, a party that consistently gets just under 20% of the vote across all districts would end up with no seats at all, although 20% is a significant proportion of the population, and in fairness is entitled to appropriate representation. This can be improved by adding more members per district, but then the legislature becomes unwieldy - in fact I would dare say it would be unwieldy even at 5 members per district in US, since it would push the number of representatives over 2000. Increasing district sizes proportionally would mitigate that, but it also decreases the connection between the elected representative and the people in their district, and thus also accountability.
It's hard if you keep single-member districts, though there are possibilitie: (e.g., assign seats to parties based on share first-preference votes across all districts, with all the same handling of minimum thresholds, etc, you would apply in party list proportional, and then elect specific candidates from the by-district elections as follows:
- If a parties total number of allocated seats is equal to the number of candidates they have remaining in districts where no candidate has been elected, elect all of those candidates.
- Otherwise, elect the candidate from the party whose currently-elected # of candidates is the smallest fraction of their allocated seats (breaking ties in favor of the largest absolute deficit) who has the greatest share of the vote in the district in which they competed.
- Repeat until all allocated seats are filled.
Voilà: all the partisan proportionality of party-list proportional, with candidates elected from single-member districts, with candidate centered voting, and no party lists.
I think practically STV or a similar system in small multimember districts (about 5 members per district) is probably a better balance of proportionality and individual candidate accountability (and results in more people having a candidate that is both local and politically acceptable than most other systems), and STV of course can scale to any level of proportionality at the expense of greater number of candidates and larger districts.
Party lists provide an easy route to partisan proportionality but eliminate direct accountability to the general electorate of individual representatives. Ideally, I think, you want both proportionality and individual accountability to the general electorate.