[EM] Comparing ranked versus unranked methods
Forest Simmons
fsimmons at pcc.edu
Tue Feb 19 09:45:51 PST 2002
On Tue, 19 Feb 2002, Adam Tarr wrote:
> The problem with Webster and PAV is not its fairness in allocation, which
> is arguably impeccable in the ideal, but rather its manipulability as
> compared to d'Hondt. Since d'Hondt has a (very slight) bias toward larger
> parties, it eliminates the incentive to split parties and encourages
> coalition building, which is crucial for PAV to work.
Good explanation. If f(n) is the representation to be alloted a party of
size n, then two parties of size n/2 "earn" total representation of
2*f(n/2). So if 2*f(n/2) is greater than f(n) there is a pressure towards
fragmentation.
More generally, if for each pair of n and m such that both f(n) and f(m)
are one or greater it is true that f(n+m) is greater than f(n)+f(m), then
there is a pressure towards fragmentation of parties down to the minimum
quota size min{n: f(n)>0}.
Forest
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