The Tragedy of Alternative Voting Methods


A couple of months ago I applied for a fellowship at The Economist. I was not accepted, but part of the application process was to write a short article. It’s just a small piece, but I still liked it enough that I thought it was worth a post (links have been added, for this post, along with some light edits):

There are few things one can get Americans on the modern left and the right to agree on, but the two-party system must be towards the top of the list. Most seem to view the power of the Republican and Democrat parties, with varying degrees of fervor and fatalism, as corrupt and duopolistic. An increasingly popular possible solution to this is to change our voting system.

Currently the US uses “first-past-the-post” (or “FPTP”) voting, in which voters endorse only one candidate, and do so absolutely. This limits how much of someone’s preferences they can communicate, rating every candidate they didn’t vote for as interchangeable. This loss of information disproportionately underrates close runner-up candidates, penalizing people for voting for their actual first choice when that first choice has a poor chance of winning. This leads to the commonly discussed “vote-splitting” effect in primaries and “spoiler” effect of third-party voting. Since all voting systems work in roughly the same way when dealing with two candidates, this incentivizes a system that funnels elections down to two candidates.

While FPTP is the most common voting system among democracies worldwide, it is notoriously bad. A group of voting experts gathered by the London School of Economics and Political Science voted on their preferred system, and the lowest scoring one was FPTP. Needless to say, they were not using FPTP to decide this. This highlights an enduring irony for election reformers. Opposition to FPTP voting is uniting, but the current front runner is not clearly the best choice.

The system getting the most mainstream attention at this point is instant-runoff voting. This system is a form of ranked voting which, rather than choosing a winner immediately, eliminates a loser for a number of rounds until only one candidate remains. The advantage of this is that if your first choice loses, your second choice can be automatically promoted to your first in the subsequent rounds. This system has earned credibility due to its use in Australian elections, and has been endorsed by influential figures in the Democratic party such as Bernie Sanders and Andrew Yang.

There are systems that may be even better however, such as the winner of the London School of Economics and Political Science vote (and the system it used for this vote), approval voting – a deceptively simple system in which people put their full support behind as many candidates as they want. There are more complex systems as well which may have even stronger theoretical performance. Score voting is like approval, except that it allows you to give a score to each candidate, and then the one with the highest score wins (similar to the star-rating systems often used for products online).

An even more complex method is economist Glen Weyl’s proposed “Quadratic Voting”, in which citizens are given an allowance of “voice credits” they can then use to purchase a number of votes equal to the square root of the number of credits spent. While even more complicated, and requiring digital aids for most people to use effectively, it has the virtuous effect of empowering people to signal how much they care about a given election or issue, not just what they most want to win.

All of these systems have to worry about splitting the momentum instant run-off currently has, and keeping our current system. Unfortunately, even if it can be replaced, the types of problems FPTP has may ironically also limit how good its challenger could be.



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