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 (1st, 2nd, 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., 3rd ranked choices can get redistributed as a 1st 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)

 

Resources:

 

Brams, S. J., & Fishburn, P. C. (2005). Going from theory to practice: the mixed success of approval voting. Social Choice and Welfare, 25, 457-474.

 

Burnett, C. M., & Kogan, V. (2015). Ballot (and voter) "exhaustion" under Instant Runoff Voting: An examination of four ranked-choice elections. Electoral Studies, 37, 41-49.

 

Endersby, J. W., & Towle, M. J. (2014). Making wasted votes count: Turnout, transfers, and preferential voting in practice. Electoral Studies, 33, 144-152.

 

Langan, J. P. (2004). Instant runoff voting: a cure that is likely worse than the disease. Wm. & Mary Law Rev., 46, 1569.

 

McDaniel, J. A. (2015). Writing the Rules to Rank the Candidates: Examining the Impact of Instant-Runoff Voting on Racial Group Turnout in San Francisco Mayoral Elections. Journal of Urban Affairs 38,3 p.387-408.

 

Marron, B. P. (2003). One person, one vote, several elections: Instant runoff voting and the constitution. Vermont Law Rev., 28, 343.

Neely, F., & Cook, C. (2008). Whose votes count? Undervotes, overvotes, and ranking in San Francisco's instant-runoff elections. American Politics Research, 36,4, 530-554.

 

Ornstein, J. T., & Norman, R. Z. (2014). Frequency of monotonicity failure under Instant Runoff Voting: estimates based on a spatial model of elections. Public Choice, 161, 1-9.

 


http://www.fairvote.org (proponents of IRV)

https://electology.org (proponents of approval and range/score voting)

http://rangevoting.org (proponents of approval and range/score voting)

Exit polls: http://archive.fairvote.org/?page=2170

 

Online news articles:


http://californiawatch.org/dailyreport/confusion-about-oakland-s-voting-system-may-have-affected-election-6491

http://californiawatch.org/dailyreport/ranked-choice-voting-complaints-mount-6839

https://psmag.com/the-curious-and-complexifying-ranked-choice-voting-system-4fc332a85ef1#.2etoglmq0

http://www.wral.com/instant-runoff-results-not-so-instant/8563987/

http://bangordailynews.com/2016/06/26/opinion/contributors/the-promise-of-a-true-majority-with-ranked-choice-voting-doesnt-add-up/

http://abc7news.com/politics/ranked-choice-voting-could-delay-oakland-mayoral-race-outcome-/380826/

http://californiawatch.org/dailyreport/critics-aim-end-ranked-choice-voting-after-sf-mayoral-race-13571