Satisfaction approval voting
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Satisfaction approval voting (SAV) is a voting system that extends the concept of approval voting to a multiple winner election. It was proposed by Steven Brams and Marc Kilgour in 2010.[1]
Contents
Description
Satisfaction approval voting aims to maximise the electorate's satisfaction, rather like proportional approval voting (PAV), however SAV calculates a voter's satisfaction differently to the way used in PAV. The satisfaction gained by a voter when a candidate they approve of is elected is equal to 1/n where n is the number of candidates that they voted for.[2] This has the effect of giving everyone a single vote that they split between the n candidates that they vote for. This makes calculating the winners much easier than for PAV,[3] as a voter's satisfaction gained for each elected candidate under this method is independent of how many of their choices have been elected, making satisfaction additive.[1]
Example
10 voters, 4 candidates, 2 seats
4 voters: ab
3 voters: c
3 voters: d
Using the methodology used in PAV:
| AB | AC | AD | BC | BD | CD | |
|---|---|---|---|---|---|---|
| ab voters' satisfaction | 4 | 2 | 2 | 2 | 2 | 0 |
| c voters' satisfaction | 0 | 9 | 0 | 9 | 0 | 9 |
| d voters' satisfaction | 0 | 0 | 9 | 0 | 9 | 9 |
| total satisfaction | 4 | 11 | 11 | 11 | 11 | 18 |
Therefore C and D win
Alternatively, making use of the system's additive satisfaction property:
| A | B | C | D | |
|---|---|---|---|---|
| ab voters - total vote | 2 | 2 | 0 | 0 |
| c voters - total vote | 0 | 0 | 9 | 0 |
| d voters - total vote | 0 | 0 | 0 | 9 |
| overall vote | 2 | 2 | 9 | 9 |
See Also
References
- ↑ 1.0 1.1 Lua error in package.lua at line 80: module 'strict' not found. Paper presented at the Annual National Conference of the Midwest Political Science Association, Chicago, Illinois, in April 2010.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
