Single-member district
Single Member systems, also called Single Winner systems, elect a single winner. These can be combined into many single member systems run independently in districts to form a Regional System.
They can be classified by ballot type:
- Plurality Voting: A valid vote can choose only one candidate
- Approval Voting: A valid vote can only give a yes or nothing to a given candidate.
- Ordinal Voting: A valid vote can rank candidates 1,2,3... (Tied rankings are permitted in some methods but not others)
- Cardinal Voting: voting A valid vote allows independent numerical values to be associated with each candidate. (The set of valid values is limited.)
Classification
They can be sub-classified by different ways to aggregate the ballots.
Plurality Voting
There is only one way to combine plurality votes.
Approval Voting and Cardinal Voting
Since Approval is the degenerate case of Cardinal Ballots they have the same A sum would give the Utilitarian_winner while a median would give the majoritarian winner.
Ordinal Voting
Borda count and Instant-runoff voting are common aggregation methods