[EM] Preferential Party List Method Proposal

[Greg Nisbet]

On Sat, Aug 13, 2011 at 6:21 PM, Dave Ketchum <davek at clarityconnect.com>wrote:

> 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.
>

Under this system, we would in fact see greater support for small parties
since it is less of a gamble. Even IF my first choice (probably a niche
party) does not get a seat, my vote will be eventually transferred to a
party that *does* have a seat. This means that I'm more likely to support my
first choice to begin with. (This isn't fool proof though in the original
formulation ... ranking other parties at all increases their weight which
helps them compete against my preferred niche party, I don't think this is a
huge vulnerability though and it can be solved by allowing greater
flexibility in rankings).

>
> 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.
>
>
I'm sure I don't have to remind you a Condorcet Winner does not always
exist. I don't completely understand your description of your method. How
does it work with parties?

>
>> 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.


My system does not have voters voting for candidates at all. In fact,
candidates needn't even exist (theoretically of course) for my method to be
well-defined. Instead people simply vote for parties, with parties that
can't get any seats dropped from the lowest weight first. Making the system
more candidate-centric could be done, but my algorithm (or class of
algorithms) is supposed to be a minimal, easily analyzable change from
non-preferential party list methods.

>
>
>> 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.
>>
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.electorama.com/pipermail/election-methods-electorama.com/attachments/20110813/2aa81705/attachment-0004.htm>