Voting Method Comparison Matrix Chart (version 10.3.16)

Created by Robin Quirke, Associate Researcher, PolicyInteractive Research

Contact: info@policyinteractive.org

Additional matrices by Ka-Ping Yee here and by Warren D. Smith here

Voting System	Ballot	Winner	Examples of Use	Proposed Pros	Proposed Cons
Plurality	Choose one candidate	Candidate with most votes wins	U.S. presidential elections, most other U.S. state and local elections	• Familiar • Simple • Maintains 2-party system • Does not require new ballots or voting machinery	• Minimally expressive of voter preferences • Disadvantages third parties • Tends to squeeze out moderate candidates (see computer simulation here) • Strategic voting (voting for less preferred candidate to keep least preferred from winning) • Selecting more than one candidate invalidates ballot (over-voting) • Maintains 2-party system • Winner may be disliked by a majority of the population • Does not require absolute majority • Mathematical model shows greatest mean (average) of voter regret
Approval	Choose (approve of) as many candidates as you want	Candidate with most votes (most-approved candidate) wins	U.N. secretary general elections, American Statistical Association, American Mathematical Association	• More expressivity than plurality voting (voters can say more about their candidate preferences) • Voters can safely vote honest favorite (no need for strategic voting) • Does not require new ballots or voting machinery/software • Proponents speculate it would increase voter turnout	• Unfamiliar • Not as expressive as range voting or IRV • Does not require absolute majority • Lacks political momentum
Range/Score	Score one or more candidates on a scale (0-2, 1-5, 0-9, etc.)	Candidate with highest average score wins	German Pirate Party elections, Some Olympic sports, Academic tests, Opinion polling, Web based product evaluations	• Most expressivity of these four voting systems (voters can say more about their candidate preferences) • Voters can safely vote honest favorite (no need for strategic voting) • Proponents speculate it would increase voter turnout • Proponents speculate it would reduce the importance of money in politics • Proponents speculate it would gradually reduce 2-party dominance • Mathematical model suggests leads to the least amount of voter regret	• Unfamiliar • Information costs (rating more than one candidate requires more voter knowledge) • Practically unused in political voting context • Lacks political momentum • May need new machines and/or software
Voting System	Ballot	Winner	Examples of Use	Proposed Pros	Proposed Cons
IRV	Rank each candidate in order of preference (1^st, 2^nd, etc.) Most jurisdictions limit choice to ranking three places for simplicity even if there are more candidates running, while other jurisdictions allow all candidates to be ranked.	Candidate with a majority of first place votes wins. If no candidate acquires an initial absolute majority (more than half the votes) counting moves to another round (runoff) where the candidate with the fewest number of first-preference rankings is eliminated and these prior round votes redistributed, the process being repeated until a candidate that achieves the required majority within any specific round of counting, wins. Caveat: reaching an "absolute voter majority" is a theoretical requirement, but not always a reality in U.S. IRV elections.	Local elections in several U.S. cities (e.g., San Francisco, Minneapolis), Oscar Best Picture, Australian Parliament elections, City of London,	• More expressivity than plurality voting (voters can say more about their candidate preferences) • Voters can vote honest favorite • Lowers some costs associated with two-round system elections (e.g., common in California elections, see California Proposition 14) • Proponents claim it reduces negative campaigning • Proponents claim it increases voter turnout • Strongest political momentum of the voting alternatives	• Unfamiliar to many • Complex calculation process • Confusion has led to over-voting and under-voting (more eliminated ballots) • Information costs (ranking more than one candidate requires more voter knowledge) • Voter fatigue in the ranking process • Critics claim decreases voter turnout • Critics worry combining two elections (e.g., two-round system in California) into one reduces public exposure to candidate positions on issues • Less sophisticated voters tend to be marginalized (e.g., choose not to vote at all, ballots disqualified because of over or under-voting) • Constitutional challenges • Can be expensive to implement • Creates a false majority (e.g., 3^rd ranked choices can get redistributed as a 1^st ranked choices; many ballots are disqualified) • Practicing jurisdictions experience time delays if runoff is necessary (not ÒinstantÓ; have to wait for ballots from least popular candidates to be redistributed) • Potential security problems if using computerized voting system (hacking) • Manual recount and verification difficult • Tends to squeeze out moderate candidates (see software engineerÕs computer simulation with explanation here) • Has not reduced 2-party dominance in Australia • Winner-turns-loser paradox (because of redistribution of ballots, increases in popularity can cause a winner to lose, and decreases can cause a loser to win; see example here, page 11)