Approval Voting
This is the third post in a series about voting systems. The first two posts were about making the case against ranked-choice voting. In those posts, I pointed out these flaws and talked about my concern that efforts to change to these systems will backfire, with voters ultimately reverting back to FPTP systems. In this post, I'm going to talk about a different voting method, approval voting, and why I think it is a better alternative to FPTP voting.
Approval voting is a simple idea - voters vote for every candidate that they approve of. Like ranked-choice voting, it potentially will force candidates to appeal to a broader group of voters. But unlike ranked-choice voting, it doesn't have the drawbacks we saw in the previous post.
To show how approval voting is different, I'll take the simulated election from the first post and simulate an approval-vote-based election. Here's what the ballots would look like:
Approval ballot: Alice, Bob
Approval ballot: Alice, Bob
Approval ballot: Alice, Bob
Approval ballot: Alice, Bob
Approval ballot: Bob, Alice
Approval ballot: Bob, Alice
Approval ballot: Charlie, Bob
Approval ballot: Charlie, Bob
Approval ballot: Charlie, Bob
Approval ballot: Charlie, Bob
And here's the result.
Candidate: Bob -- Votes: 10
Candidate: Alice -- Votes: 6
Candidate: Charlie -- Votes: 4
Winner: Bob
Now let's look for the various drawbacks we saw with RCV.
Election Spoilers
As you can see from looking through the results, the presence or absence of another candidate has no effect on the race between other candidates. This means that this method will prevent spoiler candidates and will therefore result in the best head-to-head candidate winning. In addition, there is no non-monotonicity effect as we saw with ranked-choice voting.
Real Election
Now let's look at how it performs in a real election. From the previous post, we saw that Andy Montroll would have won in all the head-to-head matchups. Therefore I think a system that elects him should be considered a success. Let's run the election and see what we get.
There is no one right way to convert ranked-choice ballots to approval ballots. It's possible that some people approved of only the first person they selected, some everyone but the last person (or possibly everyone, although that ballot would have no effect on the election). To determine how many people to put on each approval ballot, let's look at the distribution of the number of candidates voters put down on each ballot.
Many voters put all five candidates down. It's hard to say exactly how this would translate. I imagine voters generally approved of anywhere between two and four candidates, so let's try all of those for approval ballots.
Two-person approval ballot election:
Candidate: Andy Montroll -- Votes: 4699
Candidate: Bob Kiss -- Votes: 3989
Candidate: Kurt Wright -- Votes: 3943
Candidate: Dan Smith -- Votes: 3411
Candidate: James Simpson -- Votes: 342
Candidate: Write-in -- Votes: 81
Winner: Andy Montroll
Three-person approval ballot election:
Candidate: Andy Montroll -- Votes: 6094
Candidate: Dan Smith -- Votes: 5216
Candidate: Bob Kiss -- Votes: 4950
Candidate: Kurt Wright -- Votes: 4663
Candidate: James Simpson -- Votes: 999
Candidate: Write-in -- Votes: 123
Winner: Andy Montroll
Four-person approval ballot election:
Candidate: Andy Montroll -- Votes: 6590
Candidate: Dan Smith -- Votes: 5963
Candidate: Bob Kiss -- Votes: 5690
Candidate: Kurt Wright -- Votes: 5379
Candidate: James Simpson -- Votes: 2035
Candidate: Write-in -- Votes: 167
Winner: Andy Montroll
Andy Montroll wins in all cases. Although not conclusive, I think this is good evidence for the claim that approval voting would have better aligned with voter preferences for this election.
Drawbacks
I think there are some drawbacks to approval voting that are worth discussing. The main one is that, although it is simple, it is not how most people intuitively think of an election. In addition, it limits the amount of expression voters can convey. Lastly, voters can get burned while trying to be strategic, and end up with a worse result. Let's look at these drawbacks in turn.
Not Intuitive
Approval voting requires a different paradigm for thinking about elections. We think of voting in elections as voting about who you want to win, but that's not what happens in approval voting. In approval voting, it's more like saying, "I would be happy if any of these candidates win". Many voters might not like it. Large-scale adoption, like any change, would require significant voter education. It remains to be seen if voters would be amenable to this change or how long it would take.
Limited Expression
One problem with approval voting is that it does not allow the voters to adequately express their strong approval of one candidate over moderate approval of another. Many voters are thinking something along the lines of "I want candidate X to win". They might also be thinking "I would also be fine with candidate Y", but that's secondary. And the problem with approval voting is that there is no way for a voter to express ecstatic support for one candidate, approval for another, and disapproval for a third. Range voting would allow this, but that has its own issues.
Voters Trying to Be Strategic Get Burned
Because of the limited expression, some voters may try to be strategic in how they vote, and they could get burned in doing so. If a voter fails to vote for someone they do approve of, it can backfire. Let's look at an example of this.
Imagine another election with the three candidates Alice, Bob, and Charlie. Let's say voters from a certain district really like Alice, generally approve of Bob, and really don't like Charlie. Also, the voters believe that Bob is most likely to win the election, followed by Alice, followed by Charlie. Let's look at a simulation of that election.
Approval ballot: Alice, Bob
Approval ballot: Alice, Bob
Approval ballot: Alice, Bob
Approval ballot: Alice, Bob
Approval ballot: Bob, Alice
Approval ballot: Bob, Alice
Approval ballot: Charlie, Bob
Approval ballot: Charlie, Bob
Approval ballot: Charlie
Approval ballot: Charlie
Candidate: Bob -- Votes: 8
Candidate: Alice -- Votes: 6
Candidate: Charlie -- Votes: 4
Winner: Bob
Let's look at what happens if the voters try to be strategic. They think Bob is going to beat Alice, who they'd rather elect, so they don't put Bob on their ballots. Running the election, you can see that now Alice wins.
Approval ballot: Alice
Approval ballot: Alice
Approval ballot: Alice
Approval ballot: Alice
Approval ballot: Bob, Alice
Approval ballot: Bob, Alice
Approval ballot: Charlie, Bob
Approval ballot: Charlie, Bob
Approval ballot: Charlie
Approval ballot: Charlie
Candidate: Alice -- Votes: 6
Candidate: Bob -- Votes: 4
Candidate: Charlie -- Votes: 4
Winner: Alice
However, this strategy could backfire. Say they misjudged how much support there was for Charlie. Failing to vote for Bob could result in the election of Charlie, someone they didn't approve of.
Approval ballot: Alice
Approval ballot: Alice
Approval ballot: Alice
Approval ballot: Alice
Approval ballot: Bob, Alice
Approval ballot: Bob, Alice
Approval ballot: Charlie, Bob
Approval ballot: Charlie, Bob
Approval ballot: Charlie
Approval ballot: Charlie
Approval ballot: Charlie
Approval ballot: Charlie
Approval ballot: Charlie
Candidate: Charlie -- Votes: 7
Candidate: Alice -- Votes: 6
Candidate: Bob -- Votes: 4
Winner: Charlie
Primaries
It's also important to note that the introduction of approval voting will not eliminate the need for primary elections. To see that, imagine an incumbent president from the Alfa Party running against many people from the Beta Party. To create separation between the Beta candidates, Beta party members have to exclude some Beta Party candidates from their approval ballots. Ultimately, there will be no Beta Party candidate who gets an approval vote from everyone in their party. Conversely, everyone in the Alfa party will only have one candidate to vote for, so that candidate's votes won't be diluted.