Easy-to-explain Proportional (Multiwinner) elections
-
There's been lots of work on coming up with single-winner systems that are very good, but still easy to explain to the average voter--most notably STAR and score.
What about proportional (multi-winner) systems? Party-list proportional systems are easy to explain, but can only be representative along a single axis (or a handful of enumerated axes with multi-proportional representation). SNTV is dead simple to explain, but only semi-proportional.
The simplest voting system I can explain to voters is satisfaction approval voting: "Vote for all the candidates you like; your vote gets split equally between all the candidates you support, and the candidates with the most votes win." I can modify that explanation to explain PAV/SPAV just as easily: "your vote is split equally between all the winning candidates you support."
On the other hand, that explanation is only intuitive when working with Jefferson divisors. Is there a way to intuitively explain splitting votes using Webster or Hill divisors? Are there better PR systems that can be described just as easily?
-
I would consider COWPEA Lottery to be easy to explain.
Basically pick a ballot at random and all the candidates approved on that ballot are in the running for the next seat. Then keep picking ballots as a tie-break, eliminating candidates not approved on each one, unless the candidates in the running would go down to zero, in which case you ignore that ballot.
Then do the process again until all seats are filled. Non-deterministic, but simple and with great criterion compliance.
-
I suppose the procedure for COWPEA isn't super complex to explain, but the motivation or fairness of it is much harder to get across. Satisfaction approval voting and cumulative voting are intuitively very appealing--the rule is just "one man, one vote," but now you're allowed to split that vote between candidates. SPAV/PAV are almost as simple if you use Jefferson or Adams.
What about Webster divisors? There's an easy way to explain Webster's method by using a fixed-size quota, as long as house sizes can vary slightly. Divide each state's population by the average size of a congressional district, then round as normal to get their apportionment. (As a bonus, this gives you quota, and also the strongest variant of population monotonicity you could possibly get.)
Is there a similar way to explain Webster-based reweighting for PAV/SPAV?
-
@lime I'd have to think about an intuitive description for Webster divisors.
By the way, Satisfaction Approval Voting can only be described as semi-proportional. You're wasting part of your vote on candidates that aren't elected. It's like SNTV except that you can split your vote up. They both have similar problems to FPTP.
They might be easy to explain, but they're not worth explaining!
-
@lime On COWPEA Lottery, the motivation is that by picking ballots at random, then it will be on average proportional, and that over time and multiple constituencies it will be more proportional than a deterministic method because it isn't subject to rounding.
Also by picking more ballots at random as a tie-break rather than a candidate at random from the first ballot, it is further acting proportionally with respect to the candidates approved on the first ballot, so the PR goes all the way down. Plus as more ballots will be looked at, it is still a more consensual lottery than picking a candidate at random from the first ballot.
Also (non-mathematically), as a non-deterministic method, it sends the message that there are no "safe seats" and that representing the electorate is a privilege, not an entitlement.
-
@toby-pereira said in Easy-to-explain Proportional (Multiwinner) elections:
By the way, Satisfaction Approval Voting can only be described as semi-proportional. You're wasting part of your vote on candidates that aren't elected. It's like SNTV except that you can split your vote up. They both have similar problems to FPTP.
They might be easy to explain, but they're not worth explaining!You're right, of course, but that's why I like to bring up SAV as an "obvious" system with an obvious flaw (spoilers). Then I explain how PAV/SPAV fix that flaw with a minor change--split a vote only after a candidate is elected, not before.