Kristoffer: Thanks for pointing out those possibilities for how a big party can instruct its voters on how to thwart the intent of this proposed criterion. Obviously, BVP is not sufficient to ensure the transition from a two-party environment to a multiparty environment. What are your ideas on how make a stronger set of criteria to that end?
As to your note about range voting: If the rule allows a vote in which one candidate gets 99 points, another 1 point, and all others get 0 points - then that is so close to bullet voting so that it should for all intents and purposes be considered such. I want the voting system to be designed so that valid votes are significantly different from a bullet vote. ---------------------------------------- > Date: Tue, 29 Jan 2013 23:23:04 +0100 > From: [email protected] > To: [email protected] > CC: [email protected] > Subject: Re: [EM] Proposed bullet-voting prohibition criterion > > On 01/27/2013 03:45 PM, Peter Gustafsson wrote: > > > > There are lots of voting system criteria that have been described, > > but I have not seen this one - or any one like it - described > > before. > > > > Bullet-voting prohibition Criterion: "A voting system should not be > > constructed in such a way so that it is both legal and rational for a > > voter to fill in a ballot with only one party or candidate name, so > > that the voter refuses to order by preference all candidates that are > > not his first preference." > > This criterion seems to be two combined. These are: > > - It should not be possible to submit a ballot listing only one party > ("legal") > - For any ballot that includes only one party, there should exist at > least one other ballot that lists more than one party and which doesn't > make the voter worse off if he were to vote that ballot instead > ("rational"). > > I think the second here is pretty much Later-no-harm, though I share > Benham's opinion regarding methods that only pass LNHarm or LNHelp (and > not both or neither). That is, a method that passes only LNHarm > encourages random-fill (the voter adding more parties or candidates in a > random order because it can't hurt), and a method that passes only > LNHelp encourages bullet-voting. > > As for the first criterion, that's reasonable enough, but I think the > intent can be thwarted. > > > Since FPTP enforces bullet voting, it obviously fails the BVP > > criterion. In Approval voting, it is legal to vote for only one > > candidate, so it fails also. In score voting, it is legal to give 99 > > points to one candidate and 0 points to all others, so it also fails. > > All other voting systems (that I can think of right now) can be made > > compatible with this proposed BVP criterion by adding a rule that the > > voter must supply at least 4 (or whatever number sufficiently high) > > most preferred candidates, otherwise the vote is spoiled. > > It's easy to modify Approval and Range/score to pass the "legal" part of > the criterion, though. Just say that the Approval ballot is only valid > if at least two candidates are approved, or that the Range ballot is > only valid if, after removing a candidate given max score, there are > candidates with non-min score left. > > > So, what would happen if a voting system with a BVP-criterion > > enforcement would be introduced? I see two possible scenarios: > > > > 1. The big parties split into several very similar parties, so that > > hidebound voters of that party can vote a complete list of only party > > members. > > 2. The big parties do not split, and the voters of those > > parties engage in mutual burying. Their voters vote their party #1, > > then supply a long list of minor parties, so that they do not have to > > give any help to the hated other big party. Meanwhile, many 3rd party > > voters will vote one big party at the bottom, and several will > > tactically vote both big parties at #1 and #2 from the bottom. > > There's a third possibility. The parties may produce "decoy lists" that > aren't expected to get much support at all and are thus easily > controlled by the parent parties. Party voters could then vote for a > party and a randomly picked decoy list to get around the BVP limitation. > > For instance, say that party X introduces 12 pseudoparties (one for each > month) and instructs their voters to vote for X and the pseudoparty > corresponding to the voter's birth month. Then, in a majoritarian > system, the pseudoparties won't get their candidates elected (because > the parent party will always have significantly more support); and in a > proportional representation system, the method would give seats to the > parent parties and these parties' voters would be considered represented > by them, thus again giving the pseudoparties few seats. > ---- Election-Methods mailing list - see http://electorama.com/em for list info
