Mixed Member Proportional Representation (MMP)

MMP for Fair Elections

A party with 30% of the vote wins 30% of the seats

Voters decide how many seats each party wins

Single-member districts are preserved

Over forty nations use MMP systems to provide proportional representation while preserving single-member districts. With MMP we elect most representatives from traditional single-member districts. To balance party representation, we elect at-large members from open party lists.

Single-member districts have valued benefits. We know our representative, perhaps personally. We have a local advocate for problems, requests, and complaints. Our rep knows what we want and need in our community. Candidates campaign close to home; officeholders work for their neighbors. Single-winner ballots seldom have too many candidates. We are reluctant to give up these advantages.

MMP is recommended for state, county, and municipal legislatures who wish to maintain single-member districts. It would be great for the US House of Representatives, but a constitutional amendment to allow at large representatives would be required.

Multi Member District proportional representation (MMD)

The chief alternative to MMP is multi-member districts (MMD). All MMD legislators represent a specific district, you and almost all other voters likely voted for one of those representatives. Also, we enjoy simpler elections without the need to elect at-large members.

Proportional accuracy suffers because at-large seats are not used with MMD. A MMD legislature with less than five members per seat is only semi-proportional, especially if the legislature is small.

The US House of Representatives could use MMD proportional representation without a constitutional amendment. Proportional representation for the US Senate will require a constitutional amendment.

Both MMP and MMD proportional systems will represent American voters far better than our current system that locks in two party rule. We plan to publish at least two MMD articles; a proposal for the United States House of Representatives and one for state and local legislatures.

MMP is Easy

Step 1 - Vote for your District Representative in a single-winner race.
Step 2 - Vote for at large members from the Party List of your preferred party. This casts a Party Vote for your party. Party Votes determine how many seats each party wins in the legislature. A party with 55% of the Party Vote wins 55% of the seats.

BTR-Score to elect the District Representative

BTR-Score (Score voting with a bottom two runoff) is the best all-around voting method for single winner elections. It is not prone to spoilers and vote splitting, it allows voters to rate every candidate, ties are allowed. BTR-Score complies with state constitutions that call for election winners to have the “highest”, “greatest” or “largest” number of votes, or a “plurality” of the votes.

BTR-Score is a Condorcet voting method; it will always elect the candidate who can beat all other candidates one on one, if there is such a candidate. If there is no “beats all” candidate (rare) BTR-Score will elect a deserving winner, the champion of its single elimination tournament (below).
It’s easy, give your favorite candidate a top score of 6, give the worst a 0, rate the other candidates in comparison. Ties are allowed even for best and worst.

With BTR-Score, if your favorite candidate does not have a realistic chance of winning you can support both your favorite and another candidate you like who has a real chance to win.

The scores are used to seed a tournament; the candidate with the highest total score is the top seed, the lowest gets the bottom seed. The candidates with the two lowest total scores meet in the first contest of the tournament. The candidate preferred on most ballots wins. The winner meets the candidate with the next lowest total score in the second contest. The tournament continues until the survivor meets the top seeded candidate; this contest elects the winner.

If you gave candidate B a score of 5 and candidate D a 2, your vote will go to B when candidates B and D meet in the tournament. If you rated them equal your vote will not count because you have no preference between them.

The tournament is an instant runoff. If the ballots are electronically tabulated a simple algorithm can run the tournament in a few seconds. For more info, please visit our Score voting page.

How Many At-large Seats?

Most MMP legislatures have a set number of at-large seats. To ensure accurate proportional representation (PR), New Zealand’s parliament has 120 members, 72 elected from single winner districts and 48 at-large members, a 3 to 2 ratio.[^1] Small legislatures need a higher ratio of at-large seats to district seat. A large legislature will need at least a 2 to 1 ratio (400 district seats with 200 at-large seats, 600 seats total.

Consider the election of a 600-seat legislature with 400 districts seats and 200 at-large seats. If Party A wins 80 district seats and receives 25% of the Party Vote, Party A would win 100 seats (25% of 400 seats); 80 district seats plus 20 at-large seats. This example is nice and neat. In real elections, an apportionment method like Highest Averages is used to deal with the fractions.

Most PR systems have thresholds parties must meet to qualify for at large seats. For example, a party might need 3% of the Party Vote to qualify. If a party fails to qualify, they would keep the district seats they won (in most systems) but they would not win at large seats and their Party Votes would not be used to apportion at-large seats. Cutting small party representation is less proportional.

Base Ratio Method for accurate Proportional Representation (PR)

Accurate PR with a minimum number of at-large seats can be achieved using the Base Ratio Method. The downside, the number of at-large seats would change with each election. A legislature with 100 district representatives may need 15 to 30 at-large seats. The Base Ratio Method is simple; it uses basic math. Learn more on our Base Ratio Method page.

Regional Party Lists

Long party lists overwhelm voters. Regional party lists keep the lists short. Each regional list would cover several districts. If a party wins 8 at-large seats in an election with four regions, the top two party-list candidates from each region will be elected. Most elections will not be so easy.

When apportioning at-large seats, party representation is the prime criteria. At-large seats can be apportioned to achieve a regional balance of seats. However, the total number of at-large seats won by each party must not be changed.

To give voters a genuine choice among party-list candidates, open party lists need at least 50% more candidates than the maximum number of at-large seats the party might win.

Party List Voting Method

Many methods could be used to elect members from party lists. Approval, cumulative and plurality voting to name a few. BTR-Score would be an excellent choice with a minor modification. If three candidates are to be elected from a party list the BTR-Score winner gains the first seat. To fill the second seat, the single elimination tournament is rerun without the first winner. To fill the third seat the tournament is run again without both winners.

Proportional Representation for America

PR will be a game changing improvement to our political system. We will gain true representation. All elections will be competitive; our votes will not be wasted. We will neutralize the spoiler effect and slash gerrymandering. Voters and politicians will have more political parties to choose from.

Candidates will expand their appeal with positive campaigns. Negative campaigns will risk punishment from voters. Officeholders will have incentives and opportunities to build coalitions and negotiate compromises. We will be heard. We will have more power. Voters will be in charge.