[EM] C//A (was: Remember Toby)

[Juho Laatu]

On 11.6.2011, at 6.09, Dave Ketchum wrote:

> Why are we here?
> 
> It certainly made sense to come and explore.
>    . We find ourselves asking the voters to do some truncating.
>    . Counters may have to adjust counting ballots.
> 
> Among the many variant Condorcet methods there are various ways of handling cycles that are close to defining CWs - why not start from here, especially for such cycles?

I like this thinking since I have been advertising the simplicity of "elect the candidate that needs least number of additional votes to beat all others" :-). That is a clear (one possible) extension of the Condorcet criterion.

Why are we here then? I tend to think that the reason is the fact that Condorcet methods have some vulnerabilities like interest to compromise and burial. Especially burial looks bad since there some grouping can potentially make their favourite win by falsifying their preferences (compromising is less dramatic than this). In an otherwise excellent method these vulnerabilities look even worse. We don't have a tradition of using Condorcet methods in competitive elections, so we don't really know how people will react to them, and that makes us fear that they might even collapse. As a result there have been active studies on how Condorcet methods could be defended and how Condorcet voters could defend themselves in case something goes badly wrong. Since there have been lots of studies, there has been also lots of focus on these vulnerabilities. Various campaigns in favour of different methods may also seek problems in other methods, and one needs to defend against such claims. All this has made strategic questions maybe the most central topic in Condorcet related discussions. And still, we don't even know how much different strategies will be a problem in real life elections. My hunch is that they may be less of a problem than all this discussion might imply.

When we have discussed all the strategies for long, the other line of discussion, namely performance with sincere votes, has not received equal attention. I think it s also essential that when a method picks some candidate we have clear reasons why just this candidate was chosen. Otherwise the method may look just like a random collection of rules that pick a random winner. Condorcet methods are however never quite that bad since we can assume that in many elections there is a Condorcet winner and we can quite well explain why that candidate was a good choice. There are people who may not like the idea of electing sometimes someone with less first preference support than some other candidates, but we have to live with that and either claim that the Condorcet approach is the best one or at least one reasonable one (and that we have not seen any better rules that would work also in competitive majority based elections).

One more essential reason behind not having clear answers to why it is difficult to identify agree what the best methods are is the existence of cyclic group preferences. Such cyclic preferences do not follow the thinking patterns that we are used to when discussion about linear / transitive preferences. We expect the opinions of individual voters to follow these rules, but we should not treat group opinions the same way. Individuals can quite easily say which candidate they like best. But we need some completely new thinking to be able to address the question which candidate is the best for a group.

Anyway, although there are many complexities on the path, I think we should be able to find few exact formulations on which candidate could be considered to be the best. Such rules may vary depending on the needs of the society but I'm sure some of the rules are good general purpose rules too. And of course we have to take into account that we can only use rules that do not lead into problems in the area of strategies (we know that e.g. number of pairwise losses may not be a good rule in environments where people can nominate any number of candidates). If we assume that real world experiences will show that in many or most societies people can refrain from (other than marginal) strategic activities when using Condorcet, we might be in a position to pick the Condorcet method that we consider ideal from the sincere ballots and best winner point of view. And if that is not the case, maybe we can try tricks like the false polls trick that I advertised in other mails to force people back to decent voting practices rather than change the method to some other method that does not elect as good candidates with sincere votes.

All in all, even though there can be no perfect voting methods I'm quite hopeful that we can do pretty well here.

Juho