Multi-member system

Multi member systems, also called multi winner systems, are systems which elect multiple people in one election. In the context of multi- member systems, they are defined to be proportional if the Hare Quota Criterion is satisfied. This is not meant to imply anything about Proportional representation. It is common for several of these systems to be combined into a Regional System.

Bloc Systems

Bloc Systems elect all members at once under the same metric which would be used in a Single Member system.

Common examples:

• Bloc Approval Voting: Each voter chooses (no ranking) as many candidates as desired. Only one vote is allowed per candidate. Voters may not vote more than once for any one candidate. Add all the votes. Elect the candidates with the most votes until all positions are filled.
• Bloc Plurality Voting: Each voter chooses as many candidates as there are seats to be elected. Add all the votes. Elect the candidates with the most votes until all positions are filled.
• Bloc Score Voting: Each voter scores all the candidates on a scale with three or more units. Starting the scale at zero is preferable. Add all the votes. Elect the candidates with the highest scores until all positions are filled.
• Cumulative voting

Sequential Systems

Sequential systems elect winners via a repeated two step process of selection and ballot reweigting. The purpose of the reweigting is to fulfill Hare Quota Criterion.

Common examples:

• Sequential Proportional Approval Voting
• Reweighted Range Voting
• Sequential Monroe
• Allocated Score
• Sequentially Subtracted Score
• Single non-transferable vote

Optimal Systems

Optimal systems elect all members by the optimization of a quality function.

Common examples:

• Harmonic Voting
• Proportional approval voting
• Phragmén's Method
• Monroe's Method