I’ve said for years that if there is a referendum / ballot initiative to switch from first-past-the-post to anything else, always say yes. Anything is better than first-past-the-post. Having said that… I have opinions.
First of all, before choosing a voting system you have to know if there will be a single winner or many. Single-winner voting systems should not be used to run multi-winner elections because single-winner district-based voting method cannot produce a fair outcome; gerrymandering is always possible. Also, these methods pretty reliably magnify the power of large parties over small parties, which has always been frustrating to me (because I consistently dislike large parties as well as most smaller parties, and feel like there is no one to represent me). Multi-winner elections should use multi-winner voting systems! Naturally, my favorite systems are the one I designed, Simple Direct Representation, and the one that inspired it, Direct Representation, but since these systems will never happen, I’d recommend good old fashioned Proportional Representation, Mixed-Member Proportional, STV or any other proportional system that seems politically viable. Sometimes at night I dream of a meta-voting system where a country splits its legislature into two voting systems and during every election there’s a vote for which one people like better, which adjusts the relative influence of each system, and then … but never mind, no one would vote for it: it’s too democratic.
As for single-winner systems, I rank them clearly in this order:
1. Score voting (a.k.a. range voting, cardinal voting), where each candidate is rated on a scale (e.g. 0 to 5 stars, like the old Netflix. I was puzzled that Netflix killed off star-ratings; it seemed to produce more accurate and meaningful recommendations than the new up/down system. The reason given for the change was not that it didn’t work well—the system worked quite well, but people didn’t understand it. If it were up to me I’d focus on helping people understand it, rather than scrapping it.)
2. Condorcet methods, e.g. Ranked Pairs, which is based on preferential ballots (candidates in preferential order). A Condorcet method looks at each pair of candidates in isolation, with respect to all the ballots, and elects the candidate that wins a majority of the vote in every pairing against every other candidate. The problem is that there is not always a “condorcet winner”. If there are three candidates A, B, and C, it can happen that A beats B, B beats C and C beats A. So a Condorcet system must also specify how to resolve such conflicts. Ignorant people often promote “the preferential ballot” as a voting system, but a preferential ballot is just a ballot, not a voting system. IRV is far more popular than Condorcet, but it seems strictly worse, because IRV has no underlying mathematical basis, and happens to have somewhat unstable behavior and fails the monotonicity criterion. Also, I believe voters should be allowed to rank two candidates as equal (no preference between them) or “no opinion”; Condorcet can support such features, while IRV cannot.
I used to prefer Condorcet, probably because I learned about it first and liked the intuitive idea that “if a candidate is preferred by a majority of voters over all others, that candidate should win.” I changed my mind for the following reasons:
1. Range Voting, as well as its simpler cousin Approval Voting, allow the outcome of an election to be measured numerically, which lets voters understand the popularity of candidates, which is relevant in future elections. You can say things like “minor-party candidate M had an an average rating just one point behind the winner” or “the winner of the election had a lower average score than any other in history”. Condorcet does not allow this. If somebody comes up with a way to turn Condorcet or IRV results into simple numbers, I think somebody else could come up with a different way to do that, allowing confusing, competing numerical narratives about the results.
2. Score Voting allows more nuance. I can say “I like X a little more than Y, but I like Y a lot more than Z”.
3. Score Voting works far better in case the number of candidates is large. If there are 30 candidates, putting them in a single order is fairly impractical and burdensome for the voter unless ties are allowed.
4. Tallying results is easier with Score voting than Condorcet (though not as easy as Approval). Note that with computers we can calculate outcomes with an arbitrarily complex method, but computers can be hacked, so manual counting remains relevant.
5. If you wanted to know how happy people were with the outcome of an election, how might you ask them? “On a scale of 1 to 10, how happy are you with the outcome of the election?” That’s asking for a Score! Score voting simply turns this question into ballot form, so that if people answer honestly, it will maximize the average answer to the happiness question! A criticism against Score voting might explain “if you raise the preference of a less-preferred candidate L on your ballot, you could cause L to beat your preferred candidate P who you rated higher”. But if this happens because overall satisfaction of all voters is collectively higher, that’s a fine outcome. I’m open to hearing about ways the Score voting system could be gamed, but such gaming is only interesting if other systems are not similarly vulnerable to gaming. (Edit: aha, here’s the site where I learned about this idea.) The one “game” we can count on is something I’ll call “spreading”, where we spread out our true opinion on the ballot: if there are 3 candidates and my happiness would be 4⁄10 if A wins, 5⁄10 if B wins and 6⁄10 if C wins, I will spread this out to 0⁄10 for A, 5⁄10 for B and 10⁄10 for C. But every proposed voting system has something analogous to this.
Approval voting is technically a version of Score voting that gathers relatively little information from voters. Its virtues are that it is extremely simple and easy to implement, and I’m persuaded of its value on that basis. I suspect that, statistically, as a result of a large number of voters, Approval won’t perform much worse than Score voting in practice. My intuition is this: consider one hundred voters who partially approve of a candidate C; they would like to rank this person as 5⁄10, but on an Approval ballot they can’t. I suspect that roughly half of the people will “approve” of this person, so that overall the results are similar to what Score voting would produce.
I’ve said for years that if there is a referendum / ballot initiative to switch from first-past-the-post to anything else, always say yes. Anything is better than first-past-the-post. Having said that… I have opinions.
First of all, before choosing a voting system you have to know if there will be a single winner or many. Single-winner voting systems should not be used to run multi-winner elections because single-winner district-based voting method cannot produce a fair outcome; gerrymandering is always possible. Also, these methods pretty reliably magnify the power of large parties over small parties, which has always been frustrating to me (because I consistently dislike large parties as well as most smaller parties, and feel like there is no one to represent me). Multi-winner elections should use multi-winner voting systems! Naturally, my favorite systems are the one I designed, Simple Direct Representation, and the one that inspired it, Direct Representation, but since these systems will never happen, I’d recommend good old fashioned Proportional Representation, Mixed-Member Proportional, STV or any other proportional system that seems politically viable. Sometimes at night I dream of a meta-voting system where a country splits its legislature into two voting systems and during every election there’s a vote for which one people like better, which adjusts the relative influence of each system, and then … but never mind, no one would vote for it: it’s too democratic.
As for single-winner systems, I rank them clearly in this order:
1. Score voting (a.k.a. range voting, cardinal voting), where each candidate is rated on a scale (e.g. 0 to 5 stars, like the old Netflix. I was puzzled that Netflix killed off star-ratings; it seemed to produce more accurate and meaningful recommendations than the new up/down system. The reason given for the change was not that it didn’t work well—the system worked quite well, but people didn’t understand it. If it were up to me I’d focus on helping people understand it, rather than scrapping it.)
2. Condorcet methods, e.g. Ranked Pairs, which is based on preferential ballots (candidates in preferential order). A Condorcet method looks at each pair of candidates in isolation, with respect to all the ballots, and elects the candidate that wins a majority of the vote in every pairing against every other candidate. The problem is that there is not always a “condorcet winner”. If there are three candidates A, B, and C, it can happen that A beats B, B beats C and C beats A. So a Condorcet system must also specify how to resolve such conflicts. Ignorant people often promote “the preferential ballot” as a voting system, but a preferential ballot is just a ballot, not a voting system. IRV is far more popular than Condorcet, but it seems strictly worse, because IRV has no underlying mathematical basis, and happens to have somewhat unstable behavior and fails the monotonicity criterion. Also, I believe voters should be allowed to rank two candidates as equal (no preference between them) or “no opinion”; Condorcet can support such features, while IRV cannot.
I used to prefer Condorcet, probably because I learned about it first and liked the intuitive idea that “if a candidate is preferred by a majority of voters over all others, that candidate should win.” I changed my mind for the following reasons:
1. Range Voting, as well as its simpler cousin Approval Voting, allow the outcome of an election to be measured numerically, which lets voters understand the popularity of candidates, which is relevant in future elections. You can say things like “minor-party candidate M had an an average rating just one point behind the winner” or “the winner of the election had a lower average score than any other in history”. Condorcet does not allow this. If somebody comes up with a way to turn Condorcet or IRV results into simple numbers, I think somebody else could come up with a different way to do that, allowing confusing, competing numerical narratives about the results.
2. Score Voting allows more nuance. I can say “I like X a little more than Y, but I like Y a lot more than Z”.
3. Score Voting works far better in case the number of candidates is large. If there are 30 candidates, putting them in a single order is fairly impractical and burdensome for the voter unless ties are allowed.
4. Tallying results is easier with Score voting than Condorcet (though not as easy as Approval). Note that with computers we can calculate outcomes with an arbitrarily complex method, but computers can be hacked, so manual counting remains relevant.
5. If you wanted to know how happy people were with the outcome of an election, how might you ask them? “On a scale of 1 to 10, how happy are you with the outcome of the election?” That’s asking for a Score! Score voting simply turns this question into ballot form, so that if people answer honestly, it will maximize the average answer to the happiness question! A criticism against Score voting might explain “if you raise the preference of a less-preferred candidate L on your ballot, you could cause L to beat your preferred candidate P who you rated higher”. But if this happens because overall satisfaction of all voters is collectively higher, that’s a fine outcome. I’m open to hearing about ways the Score voting system could be gamed, but such gaming is only interesting if other systems are not similarly vulnerable to gaming. (Edit: aha, here’s the site where I learned about this idea.) The one “game” we can count on is something I’ll call “spreading”, where we spread out our true opinion on the ballot: if there are 3 candidates and my happiness would be 4⁄10 if A wins, 5⁄10 if B wins and 6⁄10 if C wins, I will spread this out to 0⁄10 for A, 5⁄10 for B and 10⁄10 for C. But every proposed voting system has something analogous to this.
Approval voting is technically a version of Score voting that gathers relatively little information from voters. Its virtues are that it is extremely simple and easy to implement, and I’m persuaded of its value on that basis. I suspect that, statistically, as a result of a large number of voters, Approval won’t perform much worse than Score voting in practice. My intuition is this: consider one hundred voters who partially approve of a candidate C; they would like to rank this person as 5⁄10, but on an Approval ballot they can’t. I suspect that roughly half of the people will “approve” of this person, so that overall the results are similar to what Score voting would produce.