On 23.7.2011, at 17.45, Jameson Quinn wrote: > We had a discussion about the best practical single-winner proposal, which, > while it certainly wasn't as conclusive as I'd hoped, seemed productive to > me. I think we should have a similar discussion about PR. > > Obviously, the situations in the UK and in the USA are very different in this > regard. The UK is, as far as I know, the origin of the PR movement (in the > 1860s and 1870s, liberals gained seats disproportionately as the franchise > was extended, and Conservatives looked for a "fairer" system to recoup their > losses). And it's part of Europe, where people have experience with PR. But > both the UK and the US currently elect their principal representative bodies > by district-based FPTP/plurality. > > And so I'd like to suggest that we should be looking for a PR system which > satisfies the following criteria: > > 1. Truly proportional (of course). I would be willing to support a > not-truly-proportional system, but I'm not everyone. Egregious compromises on > this issue will simply reduce the activist base, to no benefit.
What is a not-truly-proportional system? That could range from being close to proportional (=> only few seats difference to full PR) to being close to what the system is today in the USA (=> gives one or two seats to third parties). > 2. Includes a geographical aspect. People are attached to the "local > representation" feature of FPTP, whether that's rational or not. That may well make sense also in a PR system. Proportional geographical representation is a different and separate target, not necessarily a relic. > 3. No "closed list". A party should not be able to completely shield any > member from the voters. In general, voter power is preferable to party power, > insofar as it's compatible with the next criterion. > 4. Simple ballots. A reasonably-thorough voter should not have to mark more > than, say, 5 candidates or options, and an average ballot should not list > more than 20 candidates or options. Those are extreme limits; simpler is > better, all the way down to around 7 options (of which only around half will > be salient and/or viable). I hope you don't assume that all the candidates must be listed on the ballot. One could have also ballots where the voters write the number(s) of their favourite candidate. That approach allows high number of candidates. Let's say that there are 100 seats. In a fully proportional system a "party" with more than 1% support would be entitled to one seat. If you want the voters to decide who wins instead of letting the party decide you need several candidates to choose from. Let's say that this party has 5 candidates. If other parties have similar rights to nominate candidates you could end up having e.g. 100*5 candidates. That is not an exact formula and I ignored the impact of districts, but the point is that if you want to support small parties and ability to select from multiple candidates the total number of candidates and the total number of candidates per district may grow large. Does number 20 above limit the number of candidates per district? > 5. Ideally, the smoothest transition possible. If existing single-winner > districts can be used unchanged, all the better. Having both pure single-winner districts (not e.g. MMP) and full PR is possible but then you have to accept considerable inaccuracy in electing the most liked candidate in each district. I guess what you are looking for is a good balance between these incompatible (but positive) requirements. Maybe this is one reason why you would accept also less than perfect PR. > 6. Insofar as it's compatible with the criteria above, greater freedom in > voting is better. For instance, if ballots are printed with only in-district > candidates, a system which allows out-of-district write-ins is better than > one which doesn't, all other things being equal. Is the old American tradition of allowing write-in candidates included in your list of requirements? > > My proposal for SODA-PR satisfies and surpasses all 5 criteria. Other systems > which do reasonably well: > -I've seen a proposal for single-member districts and open party lists. This > is similar to my SODA-PR system, except that it requires that all candidates > in a party approve the same party set. As such, it is strictly worse on > criterion 3, without being notably better on any of the other criteria. It is > more conventional, though. > -Multimember districts, with some system inside each district. > -Mixed member systems. One possible approach (with accurate PR) is to first allocate the seats to parties at national level and then allocate those seats to (probably multimember) districts (in a geographically proportional way). One approach that allows high number of candidates and simple ballots is to allow voters to rank candidates of one single party in one single region only. One may also limit the maximum number of ranked candidates heavily since that vote will support the correct party anyway (with its full strength of one vote). Is party internal proportionality a requirement or would e.g. basic open lists do? (And if you want party internal proportionality, would trees or candidate given preference order (without option for voter given preference order, as in SODA) be enough, or do you require any voter given preference order to be supported?) Juho > > Still, I would argue that SODA-PR sets a high water mark on all the criteria > I mentioned, and is therefore the system to beat. I'm somewhat surprised that > it hasn't gotten more comments. I'd especially like it if people could come > up with clever mechanisms to (virtually) ensure that discarding whole ballots > gives the same results as fractional ballot reweighting, using some > probabilistic wording or process. (For instance: "When choosing seat N+1, > select the previous N seats with random discarding until you get the same > answer three times"... needs work I think. Or a proof that the fractional > process is always the highest-probability result of the random-discard > process - which I'm sure is very close to true, but not sure is true - so > that you could write a statute to just say "highest-probability result".) > > JQ > ---- > Election-Methods mailing list - see http://electorama.com/em for list info ---- Election-Methods mailing list - see http://electorama.com/em for list info
