[EM] Party-based top two with approval

Kevin Venzke stepjak at yahoo.fr
Sun Mar 25 08:32:54 PDT 2018

 Hi Rob,
    Le lundi 19 mars 2018 à 00:44:35 UTC−5, Rob Lanphier <robla at robla.net> a écrit :  
 > One way that it could work: the *overall* approval vote winner is
> automatically on the ballot (regardless of whether they the winning
> party or not).  But then, the top vote getting party would have the
> opportunity to put a candidate on the ballot if their voters made a
> different choice.  Let me try tweaking my example.  Once again, 100
> people voting.  I'll propose a tweak to my example ballot:
Well, what bothers me is that it can happen that a Democrat is the overall approvalwinner while the Democratic party list is the party list winner, simply because theirrivals are divided a bit. If you have only Democrats advance in that scenario then itseems like the two rounds have less purpose.
I think the design should make sure that the same voters can't supply both finalists,but without raising the question of whether a party can do "so well" that we have toforcibly take one of the selections away from them.
>I suspect that a much simpler version that doesn't involve parties at
>all might be superior.  Kevin's earlier suggestion looks really
>> 1. Round one is an approval ballot. Advance the approval winner, against the
>> candidate with max AO against him. That is, remove the ballots approving the
>> winner and advance, as challenger, whoever is the new approval winner. This
>> doesn't require a first-round auto-win rule (but could support one too, I guess).
>The thing I like about this first system Kevin proposes is that it
>seems reasonably likely to satisfy this criteria: two candidates for
>whom the largest proportion of voters approves of at least one of the
>two candidates.  Kevin's system #1 has the benefit of simplicity.  A
>potential downside of that system is that having a popular leading
>candidate means that many fewer voters are involved in choosing the
>runner up (e.g. if the top candidate gets 85% approval, then the
>runner up is chosen by the 15% that didn't like the top candidate).
Yes, though if it's 85% I think the unfortunate thing might be that we would haveto go on to have a second round at all. I think if a candidate can get majority approval (especially on a ballot without ranks) the biggest concern is addressed.
Maybe stating the obvious but you could if you want directly advance the twocandidates who maximize the number of voters who approved at least one. A majordownside of doing that would be that the overall approval winner isn't guaranteedto be one of the finalists.
There are some interesting questions about what we're trying to do when pickingfinalists. The overall approval winner is a good estimate for the best overall candidate, so it seems bad to omit him. The two candidates who "maximizeparticipation" (let's say) is more like an estimate of who the voters think are the main contenders.
Regarding the 85%/15% scenario I almost want to say "use proportional approval voting so the 85% can contribute somewhat in picking the second finalist aswell." That would probably give you a more competitive second round.
Without getting into proportionality (which isn't directly related to the goal of thefirst round) one could probably come up with an equation that balances eachcandidate's likelihood of being able to beat the approval winner pairwise, withtheir likelihood of simply being a clone of the approval winner.
>> I wonder if such a system would be "stable," as in, have general acceptance.
>> A party in the position of wanting to forfeit their seats because of rogue
>> candidates trying to piggyback, I can imagine would start to argue for a
>> change in the rules. On the other hand if a seat is forfeited it's
>> presumably lose-lose for the party, voters, and the candidate. So maybe it's
>> a threat that would never actually happen.
>An example of where the party could decide to forfeit could be a
>situation similar to the one Republicans face in Illinois:
>That particular example is one where the Republicans claim they want
>to jettison the candidate, but don't have the means to do it.
>One thing that I think makes my system resilient against a party
>forfeiting a popular candidate is that the party could be held to
>account in a subsequent election.  Forfeiting a popular candidate
>would make it far less likely for the voters who voted for that party
>to vote for that party again.
I would only see forfeits occurring if the party views the candidate's supportersas "invasive" in the first place, so they wouldn't be concerned about losing thesupport. I can't see a party forfeiting any candidate who is at least somewhat appropriate for the list.
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