Voting Theory studies how to take individual rankings of voters and aggregate them to form the global ranking.
Examples:
For this notation we define the following relations (Voting Theory Relations)
A voting mechanism (or voting procedure or voting method) takes a collection of votes (individual preferences of the candidates from set $A$) and forms the global ranking. Usually it choses a single candidate from the set $A$.
There are several voting procedures:
How to characterize "good" voting methods?
There are several criteria
PV | 2PV | Borda | Cond. | |
---|---|---|---|---|
Monotonicity | ✔ | ✘ | ✔ | ✘ |
Solution Existence | ✔ | ✔ | ✔ | ✘ |
Manipulation | ✘ | ✘ | ✘ | ✘ |
Separability | ✔ | ✘ | ✔ | ✔ |
Condorcet Fairness | ✘ | ✘ | ✘ | ✔ |
Other principles: