[EM] Preferential Party List Method Proposal

[Dave Ketchum]

Glad to see thinking, though we part company on some details.

On Aug 13, 2011, at 5:25 PM, Greg Nisbet wrote:

> All current forms of party list proportional representation have  
> each voter cast a vote for a single party. I say this is inadequate  
> since a small party can be eliminated and hence denied any  
> representation (this is particularly relevant if the legislature has  
> a threshold). However, votes for a party that doesn't have  
> sufficient support to win any seats in the legislature are simply  
> wasted. Thus I propose an alternative method.

That some party may get zero seats, that does NOT make their attempt a  
pure waste:
.    If they are growing, they are on the way - and a warning to other  
parties that their apparent goals deserve more attention - perhaps to  
be honored by those who do get seats.

I would base the voting and counting on the ranking we do in Condorcet  
for single seats - same N*N matrix and whoever would be CW be first  
elected, with next the one who would be CW if the first CW was excluded.
.     If the above could elect too many from any one party, exclude  
remaining candidates from that party on reaching the limit.
.     Note that the N*N matrix has value that does not often get  
mentioned - it is worth studying as to pairs of candidates, besides  
its base value of deciding the election.
>
> Each voter votes for as many parties as they wish in a defined  
> order. My vote might be democrat>green>libertarian>republican or  
> something like that.
>
> Anyway, first we calculate each party's "weight". Weight is  
> calculated simply by counting the number of times the party appears  
> on a voter's ballot in any position (this should be reminiscent of  
> approval voting). Each party also has a status "hopeful", "elected",  
> or "disqualified".
>
> Next, pick your favorite allocation method. D'Hondt, Sainte-Laguë,  
> Largest Remainder, anything else you can think of, with or without a  
> threshold.
>
> We then use this allocation method to determine each party's mandate  
> if everyone voted for their first preference. If every hopeful party  
> has at least one seat, then all the hopeful parties are declared  
> elected. If at least one hopeful party has no seats at all, the  
> party with the lowest weight is disqualified, its votes are  
> redistributed, and the allocation is done again with the new list of  
> hopeful parties.

I see "first preference" and think of avoiding IRV's problems - which  
the above ranking attends to.

I am assuming candidates identified with their parties, and parties  
getting seats via their candidates getting seats.  Thus, once all the  
seats get filled, remaining parties - due to their lack of strong  
candidates - get no seats.
>
> This method has some advantages over traditional systems. People  
> would not be motivated to betray their favorite party for fear that  
> it will lack enough support to win any seats in the legislature and  
> hence their vote would be wasted. This method can also be slightly  
> modified into a cardinal method, with a voter's first choice being  
> defined as the highest rated party on their ballot remaining and  
> weight being calculated by the arithmetic mean of a party's rating à  
> la Range Voting. This class of voting method is probably compatible  
> with MMP, but I haven't yet worked out the details of how that would  
> work.