[EM] Re to KM wrt 3 seat Largest Remainder Hare and Loring Ensemble Rule.

[Kristofer Munsterhjelm]

David L Wetzell wrote:

> 
> On Fri, Nov 18, 2011 at 7:14 AM, Kristofer Munsterhjelm 
> <km_elmet at lavabit.com <mailto:km_elmet at lavabit.com>> wrote:
>> 
>>     Loring argues that Plurality councils can swing wildly and deny
>>     representation to people who should be represented, while PR
>>     councils can still be off-center due to kingmaker scenarios, and
>>     that one should therefore pick a center that can break ties while
>>     not giving any voting bloc undue power.
> 
> 
> My approach replaces STV with LR Hare, I guess I don't really care 
> whether rankings get used or not, but I do like having fewer seats with 
> PR with a Hare Quota, so we can avoid those arbitrary percentage 
> restrictions.  It lets third parties decide who's the party-in-power but 
> helps the party-in-power get more seats so they can get things done if 
> they are generally popular, or able to win many of the single-winner 
> elections.   

Personally, I think Sainte-Lague is a more proportional approach than 
LR-Hare. In being a divisor method, it can avoid the population-pair 
monotonicity problem, and by measures of proportionality, it is usually 
about as good as LR-Hare.

Unfortunately, there's no Sainte-Lague (or divisor method) version of 
STV yet. The closest I know of is my "Set Webster" method, which 
combines a divisor method and the concept of solid coalitions. It is 
(most likely) monotone, but not so much better than STV that it's worth 
it to switch unless you value monotonicity above all else or are 
interested in new methods in and of themselves.

If you want party list, though, use Sainte-Lague (or Webster, same 
thing). For the same reason, I think that congressional apportionment 
would be better done by Webster's method (as it were, once), than with 
the current Huntington-Hill algorithm.

>>    He then proposes to use STV, but shield the CW from losing. The
>>    Condorcet winner represents the center or common consensus position,
>>    while the other winners represent the diversity of opinion among the
>>    people. Because the process is done inside a single method, in the
>>    case the CW is off-center, the proportional representation aspect of
>>    the algorithm will even this out by compensating.
> 
> 
> The link you gave me though tends to weigh stronger for the 2nd version, 
> which is easier to explain to voters by virtue of how it combines two 
> already existing elections...

I suppose the first version is more like MMP and the second version is 
more like parallel voting. That is, the first compensates and the second 
just runs in parallel.

You might be able to get something more easily understood yet retaining 
some of the compensation part of the first version, by doing something 
like this: first elect the single winner/s. Then start STV with the 
single winner/s marked as elected (and thus with vote transfers already 
done).

>>     The same sort of shielding could be used in any type of multiwinner
>>     system. If it's sequential, you just keep the CW from being
>>     eliminated. If it's combinatorial (like Schulze STV), you only
>>     consider those sets of winners that include the CW.

> dlw:If I was gung-ho on getting the CW elected that'd be really great, 
> but I don't expect great things of the ranking choices of low-info 
> voters like we have a lot of in the US.  Does it matter the ratios?  Cuz 
> I really like 3:1 multi-winner and single-winner. 

The ratios matter to some extent, which we can see by considering the 
extremes. If you have infinity PR seats to each single-winner seat (i.e. 
no single-winner seats at all), then you have a PR council. If you elect 
only single-winner seats, then you get a bunch of the group closest to 
center, starting at the center and winding its way out (if the method is 
good, that is).

So the balancing point depends on how much you value single-winner 
balance against PR diversity. You could probably do some calculations to 
find out to what degree increasing the single-winner share lowers the 
probability of small-party kingmakers getting undue power, but 
ultimately, you'd have to make a value judgement.