All voting systems violate intuitively desirable conditions, so noting that some system violates some condition is in itself no reason to favor other systems. One needs to look at the full picture, see what conditions are violated by what systems, and pick the system that minimizes weight-adjusted violations. (There is a clear parallel here between voting theory and population ethics: impossibility theorems have demonstrated in both fields that there exists no voting rule or population axiology that satisfies all intuitively plausible desiderata, so violation of a condition can’t be adduced as a reason for rejecting the rule or axiology that violates it.)
But there is a much better approach, namely, to assess different systems by their “voter satisfaction efficiency” (VSE). Instead of relying on adequacy conditions, this approach considers the preferences that the electorate has for rival candidates and deals with them using the apparatus of expected utility theory. Each candidate is scored by the degree to which they satisfy the preferences of each voter, and then rival voting systems are scored by their probability of electing different candidates. Monte Carlo simulations independently performed by Warren Smith, Jameson Quinn and others generally find that approval voting has higher VSE than instant-runoff voting, and that both approval voting and instant-runoff voting have much higher VSE than plurality voting.
Given these results, I think the priority for EAs is to support whichever alternatives to plurality voting are most viable in a particular jurisdiction, rather than obsess over which of these alternatives to plurality is the absolute best. Of course, I also think it makes sense to continue to research the field, and especially refine the models used to compute VSE. What EAs definitely shouldn’t do, in my opinion, is to spend considerable resources discrediting those alternatives to one’s own preferred system, as FairVote has repeatedly done with respect to approval voting. Much more is gained by displacing plurality than is lost by replacing it with a suboptimal alternative (for all reasonable alternatives to plurality).
(In case it isn’t obvious, I’m definitely not saying that you have done this in your essay; I’m rather highlighting a serious failure mode I see in the “voting reform” community that I believe we should strive to avoid.)
Hello, I think you make a good point, about the necessity to carefully weigh the up- and downsides of each system.
I do not have a strong view on which alternative voting system is best, since I haven’t looked into it deeply enough. Still I want to address this proposition:
Much more is gained by displacing plurality than is lost by replacing it with a suboptimal alternative (for all reasonable alternatives to plurality).
I mostly agree with this position, especially in scenarios where no other option is realistically on the table. However, I do want to point out, that adopting a sub-optimal system can have a considerable cost and that it is not entirely obvious that this cost is irrelevant relative to the gains obtained from switching away from the status quo; in particular, if one believes that the difference in outcomes between two alternative voting systems is big.
For instance, one might assume alternative voting system B to lead to much better results than system A. If this were the case, then switching to A (the weaker system), though (probably) better than the status quo in itself, could still lead to outcomes that are worse than if the switch had not happened. This is for 2 main reasons:
First, as Tobias points out, countries do not change their voting system frequently. Hence this sub-optimal system A might potentially stick around for a century to come, before maybe being changed to the better alternative B. It might be preferable to postpone the switch by a few years, hopefully increasing the odds of switching to B instead of A.
Secondly, this new system A will inevitably be questioned by the electorate and the media. If system A then yields controversial results that are not obviously better than the results one would have got with the status quo system, the whole switch might be viewed as a mistake by the general population. This might even lead to less trust in the political system, though probably only in the short run. Still, a negative experience of this kind, may not only have short-term bad consequences for the country itself in the form of further erosion of trust, but could also discourage other countries from switching away from their respective status quo system for years to come.
Of course, I’m not arguing that switching should be postponed until absolute certainty of one system being better than all others is reached. (That point will probably never come.)
And, of course, I also acknowledge, that the opposite of the described scenario might happen, i.e. that one country switching might encourage others to do so, rather than discourage.
All I’m saying is that there is a case against switching and that therefore, not any system that seems preferable to the status quo ought to automatically be endorsed.
Thanks to your comment, I can now endorse what you said as a more accurate and nuanced version of the position my previous comment tried to articulate. Agreed 100%.
I’m not entirely convinced that VSE is the right approach. It’s theoretically appealing, but practical considerations, like perceptions of the voting process and public acceptance / “legitimacy” of the result, might be more important. Voters aren’t utilitarian robots.
I was aware of the simulations you mentioned but I didn’t check them in detail. I suspect that these results are very sensitive to model assumptions, such as tactical voting behaviour. But it would be interesting to see more work on VSE.
What EAs definitely shouldn’t do, in my opinion, is to spend considerable resources discrediting those alternatives to one’s own preferred system, as FairVote has repeatedly done with respect to approval voting. Much more is gained by displacing plurality than is lost by replacing it with a suboptimal alternative (for all reasonable alternatives to plurality).
I suspect that these results are very sensitive to model assumptions, such as tactical voting behaviour. But it would be interesting to see more work on VSE.
I agree with this. An approach I find promising is that of Nicolaus Tideman & Florenz Plassmann. In one study, the authors consider several different statistical models, use them to simulate actual elections, and rank the models by how best they approximate actual results. Then, in a subsequent study, the authors use the top-ranking model from their previous study to evaluate a dozen or so alternative voting rules, finding that plurality, anti-plurality, and Bucklin perform worst. As far as I’m aware, this is the only example of an attempt to assess voting rules by conducting simulations with a model that has been pre-fitted to actual election data. I believe that extending this approach may be among the most impactful research within this cause area.
Monte Carlo simulations independently performed by Warren Smith and Jameson Quinn generally find that approval voting has higher VSE than instant-runoff voting, and that both approval voting and instant-runoff voting have much higher VSE than plurality voting.
A priori, I think this could end up being quite sensitive to the distributions of votes they used. Did they choose them based on surveys/polls of voter preferences?
A variety of utility distribution models were tried, and it turned out not to matter very much.
The simulations by N. Tideman had methodological flaws and didn’t measure the right thing, thus being approximately as useful as a random coin flip in this mathematician’s view.
I think it’s worth being aware of lock-in effects; while I agree that it’s unproductive to put down alternative approaches, it’s also important to do what we can to avoid locking in a suboptimal choice- if Ranked Choice gets locked in over Approval Voting, and if Approval is actually better, it may be very hard to change it in the future, leading to much long-term disutility, perhaps even more than if the shift away from FPTP takes a little longer in the process of getting it right.
But I do agree that bickering and putting alternatives down probably isn’t the best way to mitigate lock-in
Thanks for writing this—I think electoral reform is an interesting and important cause area.
All voting systems violate intuitively desirable conditions, so noting that some system violates some condition is in itself no reason to favor other systems. One needs to look at the full picture, see what conditions are violated by what systems, and pick the system that minimizes weight-adjusted violations. (There is a clear parallel here between voting theory and population ethics: impossibility theorems have demonstrated in both fields that there exists no voting rule or population axiology that satisfies all intuitively plausible desiderata, so violation of a condition can’t be adduced as a reason for rejecting the rule or axiology that violates it.)
But there is a much better approach, namely, to assess different systems by their “voter satisfaction efficiency” (VSE). Instead of relying on adequacy conditions, this approach considers the preferences that the electorate has for rival candidates and deals with them using the apparatus of expected utility theory. Each candidate is scored by the degree to which they satisfy the preferences of each voter, and then rival voting systems are scored by their probability of electing different candidates. Monte Carlo simulations independently performed by Warren Smith, Jameson Quinn and others generally find that approval voting has higher VSE than instant-runoff voting, and that both approval voting and instant-runoff voting have much higher VSE than plurality voting.
Given these results, I think the priority for EAs is to support whichever alternatives to plurality voting are most viable in a particular jurisdiction, rather than obsess over which of these alternatives to plurality is the absolute best. Of course, I also think it makes sense to continue to research the field, and especially refine the models used to compute VSE. What EAs definitely shouldn’t do, in my opinion, is to spend considerable resources discrediting those alternatives to one’s own preferred system, as FairVote has repeatedly done with respect to approval voting. Much more is gained by displacing plurality than is lost by replacing it with a suboptimal alternative (for all reasonable alternatives to plurality).
(In case it isn’t obvious, I’m definitely not saying that you have done this in your essay; I’m rather highlighting a serious failure mode I see in the “voting reform” community that I believe we should strive to avoid.)
Hello, I think you make a good point, about the necessity to carefully weigh the up- and downsides of each system.
I do not have a strong view on which alternative voting system is best, since I haven’t looked into it deeply enough. Still I want to address this proposition:
I mostly agree with this position, especially in scenarios where no other option is realistically on the table. However, I do want to point out, that adopting a sub-optimal system can have a considerable cost and that it is not entirely obvious that this cost is irrelevant relative to the gains obtained from switching away from the status quo; in particular, if one believes that the difference in outcomes between two alternative voting systems is big.
For instance, one might assume alternative voting system B to lead to much better results than system A. If this were the case, then switching to A (the weaker system), though (probably) better than the status quo in itself, could still lead to outcomes that are worse than if the switch had not happened. This is for 2 main reasons:
First, as Tobias points out, countries do not change their voting system frequently. Hence this sub-optimal system A might potentially stick around for a century to come, before maybe being changed to the better alternative B. It might be preferable to postpone the switch by a few years, hopefully increasing the odds of switching to B instead of A.
Secondly, this new system A will inevitably be questioned by the electorate and the media. If system A then yields controversial results that are not obviously better than the results one would have got with the status quo system, the whole switch might be viewed as a mistake by the general population. This might even lead to less trust in the political system, though probably only in the short run. Still, a negative experience of this kind, may not only have short-term bad consequences for the country itself in the form of further erosion of trust, but could also discourage other countries from switching away from their respective status quo system for years to come.
Of course, I’m not arguing that switching should be postponed until absolute certainty of one system being better than all others is reached. (That point will probably never come.)
And, of course, I also acknowledge, that the opposite of the described scenario might happen, i.e. that one country switching might encourage others to do so, rather than discourage.
All I’m saying is that there is a case against switching and that therefore, not any system that seems preferable to the status quo ought to automatically be endorsed.
Thanks to your comment, I can now endorse what you said as a more accurate and nuanced version of the position my previous comment tried to articulate. Agreed 100%.
I’m not entirely convinced that VSE is the right approach. It’s theoretically appealing, but practical considerations, like perceptions of the voting process and public acceptance / “legitimacy” of the result, might be more important. Voters aren’t utilitarian robots.
I was aware of the simulations you mentioned but I didn’t check them in detail. I suspect that these results are very sensitive to model assumptions, such as tactical voting behaviour. But it would be interesting to see more work on VSE.
Strongly agree with this!
I agree with this. An approach I find promising is that of Nicolaus Tideman & Florenz Plassmann. In one study, the authors consider several different statistical models, use them to simulate actual elections, and rank the models by how best they approximate actual results. Then, in a subsequent study, the authors use the top-ranking model from their previous study to evaluate a dozen or so alternative voting rules, finding that plurality, anti-plurality, and Bucklin perform worst. As far as I’m aware, this is the only example of an attempt to assess voting rules by conducting simulations with a model that has been pre-fitted to actual election data. I believe that extending this approach may be among the most impactful research within this cause area.
A priori, I think this could end up being quite sensitive to the distributions of votes they used. Did they choose them based on surveys/polls of voter preferences?
A variety of utility distribution models were tried, and it turned out not to matter very much.
The simulations by N. Tideman had methodological flaws and didn’t measure the right thing, thus being approximately as useful as a random coin flip in this mathematician’s view.
Yeah, see my reply to Tobias.
I think it’s worth being aware of lock-in effects; while I agree that it’s unproductive to put down alternative approaches, it’s also important to do what we can to avoid locking in a suboptimal choice- if Ranked Choice gets locked in over Approval Voting, and if Approval is actually better, it may be very hard to change it in the future, leading to much long-term disutility, perhaps even more than if the shift away from FPTP takes a little longer in the process of getting it right.
But I do agree that bickering and putting alternatives down probably isn’t the best way to mitigate lock-in