Proportional Subset Voting: Difference between revisions

Ballot use range [-MAX,MAX]. N is the number of winners.

The following example shows how scores S are obtained from a vote:

N = 2 (winners)

Subsets

A,B: 4/1 + -4/2 = 2

A,C: 4/1 + 0/2 = 4

A,D: 4/1 + 2/2 = 5

B,C: -4/1 + 0/2 = -4

B,D: -4/1 + 2/2 = -3

C,D: 0/1 + 2/2 = 1

A,D[5] A,C[4] A,B[2] C,D[1] B,D[-3] B,C[-4]

3 converted votes:

A,D[5] A,C[4] A,B[2] C,D[1] B,D[-3] B,C[-4]

A,D[2] A,C[4] A,B[-4] C,D[7] B,D[-3] B,C[1]

A,D[4] A,C[5] A,B[1] C,D[2] B,D[-4] B,C[-3]

A,D[11] A,C[13] A,B[-1] C,D[10] B,D[-10] B,C[-6]

The winner is {A,C}

Considering one vote, a score S is obtained for each subset of N candidates. This procedure is applied to all votes and returns converted votes.

Considering the subsets as single candidates, a Single-Winner system applicable on the converted votes, is used to obtain the winning subset.

''The way of calculating S and the [[Single Member system|Single-Winner system]] chosen, determines the variant of Subset Voting.''

Thiele method uses range [0,MAX] and divides the values by <math>\begin{equation}i\end{equation}</math> with <math>\begin{equation}i=1,...,N\end{equation}</math>.

PSV uses range [-MAX,MAX] and divides the values by <math>\begin{equation}2^i\end{equation}</math> with <math>\begin{equation}i=0,...,N-1\end{equation}</math>.