Choice Voting, also known as Ranked Choice Voting or the Single Transferable Vote, is an election system used to elect several candidates at a time, as in a City Council or multi-member legislative district. In single-winner elections, the system often goes by the name Instant Runoff Voting. Choice Voting ensures that the election outcome is an accurate cross-section of voters' preferences. As with all voting systems, there are tradeoffs. Among its biggest—which has nothing to do with how useful it is—is that it's not as intuitive as traditional voting methods.
Choice voting works by voters ranking the candidates in order of preference. If your top choice loses or wins with votes to spare, your vote goes to your next choice. After a choice voting election, each elected candidate represents a distinct equal-sized group of like-minded voters.
Voters rank the candidates in order of preference: 1, 2, 3, and so on. You can rank as many or as few as you want. Ranking more choices cannot hurt your higher-ranked choices.
Say we're electing 4 candidates. Choice voting elections are tallied in the following way. First, the winning threshold is calculated. Take the total number of voters and divide by the number of seats plus one. In our case, the winning threshold is 20% of the vote.
Then the top choices are counted. If no candidate reaches the winning threshold, the last place candidate is eliminated. If your ballot went to that candidate, your vote transfers to your next choice. All the ballots are then recounted.
If some candidate does reach the threshold, that candidate is elected and their excess vote is transferred. For example, if the threshold is 1000 and the candidate received 1500 votes, one third of their vote is excess. If you voted for that candidate, one third of your vote transfers to your next choice listed.
This process continues round by round until all seats are filled. In the end, each elected candidate represents a distinct group of (in our example) 20% of the voters. Go to the ASUCD Elections web site to see an actual round-by-round tally of an ASUCD election.
Choice Voting is being used by or explored in several countries, including Canada, New Zealand, Scotland, and some cities and organizations in the United States. Locally, UC Davis students use Choice Voting to elect the ASUCD Senate (and ASUCD President). Some cities, including Burlington VT, have rescinded choice voting.
In the November 2006 Election Davis passed Measure L, which advised the city to consider using Choice Voting for its local elections. History of Choice Voting in Davis will provide a detailed look at the process of getting Choice Voting passed by the City of Davis.
Choice voting was on the November 2006 Davis city ballot as measure L. For more information about the campaign, check out DavisChoiceVoting.org. The city of Davis is interested in using Choice Voting for City Council elections. The Davis City Council formed a 9-member Davis Governance Task Force to "study issues related to governance" for six months. The Task Force paid close attention to Choice Voting and agreed (with only one abstention) to recommend that the city of Davis adopt Choice Voting. A group of concerned citizens calling themselves Davis Citizens for Representation was formed to educate the city about the benefits of using Choice Voting.
Choice Voting Variations
There are slight variations in how choice voting elections can be tallied, and each has its advantages and disadvantages. Mathematicians have proven that there is no "perfect" voting system. But that does not stop some people from trying to find the perfect implementation of choice voting.
For example, some argue that ASUCD's method of Choice Voting allows effective tactical voting1. Here's an example from ASUCD's Winter 2005 election:
Say you like Rob Roy and Kristen Birdsall in that order. If you had voted Rob Roy(1), Kristen Birdsall(2), your vote would have counted approximately 3/4 for Rob Roy and 1/4 for Kristen Birdsall. However, if in advance you thought Rob Roy would win and Mohammad had no chance of winning, you could gamble and vote Mohammad(1), Rob Roy(2), Kristen Birdsall(3). If the vote turned out as you predicted, your vote would go 100% to Kristen Birdsall. In case Rob Roy did need your vote after all, he would still receive it. The risk is that if Mohammad won, you'd be stuck with that.
More advanced implementations of Choice Voting, such as Meek's Method, reduce this possibility. Even though the possibility for strategic voting will always exist in some form for Choice Voting, it is much more difficult to exploit than in plurality or block voting. For example, in plurality voting, strategic voting is easy. Many people vote for the candidate that has the best chance of winning (e.g. Nader/Gore), even if they dislike the candidate more.
One interesting feature of Choice Voting is that it doesn't consider the weight of preferences, merely their ranked order. For instance, it doesn't matter how much a voter prefers Rob to Kristen, as all that matters is that Rob is ranked ahead of Kristen on the ballot. There are other voting systems that attempt to use the weight of preferences to determine the result (eg Borda Counts, Cumulative Voting, and Range Voting), however these systems are open to a fairly obvious form of tactical voting: exaggerating the difference, such as by ranking your second preference last.
However, most Choice Voting supporters might consider the fact the Choice Voting doesn't use a "weights" system to be a good thing. When the voter is allowed to assign weights to candidates they naturally respond by voting tactically. "Cumulative voting" is an admittedly tactical voting system that's distinct from choice voting in that it doesn't use a single transferable vote. Results from a Cumulative voting election will not be as proportional as those from a Choice Voting election. The fact Choice Voting works in a round-by-round fashion and does not allow voters to easily tactically vote means that the final result more accurately represents the preference of the entire body of voters as a whole.
- Flash animation showing how it works
- Video of how choice voting would work in Great Britain pending referendum on 5/5/11
- Wikipedia article on STV
- Wikipedia article on IRV
- Davis Citizens for Representation (DavisChoiceVoting.org) — Davis-based Choice voting advocacy group
- Davis Governance Task Force
The possibility for Choice Voting in Davis was one signature away!
AB1294 was vetoed on October 12th, 2007 by Governor Schwarzenegger. He released a press release stating why (see below). AB1294 would have allowed all California cities and counties to use choice voting regardless of their charter status.
This bill could have been a critical step toward adoption of choice voting in Davis. Currently state law forbids general law cities, like Davis, from choosing their electoral system. As the law currently stands, Davis would have to become a charter city before it could start using choice voting. AB1294 would have removed that roadblock.
Davis Citizen's for Representation made a sample letter to Governor Schwarzenegger that was available to people who wanted to contact the governor.
Governor Schwarzenegger's Veto Statement
I am returning Assembly Bill 1294 without my signature.
This bill would allow cities and counties, subject to voter approval, to conduct a local election using a ranked voting system. This represents a drastic change to the way we vote. Although there are some proponents for ranked voting, which allows for so-called "instant runoff" elections, I am concerned that we don't yet know enough about how voters will react to such a dramatic change in the way they vote. For instance, charter cities and counties already have the right to hold ranked voting elections, yet only one city has done so thus far, and that was on a trial basis only.
Further, the machines necessary to implement ranked voting are not widely available nor have any been certified by the Secretary of State. As the Secretary of State recently decertified the vast majority of electronic voting machines used for traditional elections, it is premature to even contemplate moving to ranked voting tomorrow until we have resolved any issues with the machines needed for how we vote today.
I'm fairly certain that STV is not being used or considered anywhere in Canada currently (though that may be wrong); it was the subject of a referendum in British Columbia in 2005 which failed to achieve the 60% threshold needed to pass it. Most Canadian advocates of proportional representation tend to support a different variant, in which there are candidate lists at a national level as well as local MPs elected either by something like STV or just classic First Past the Post. This is closer to the German model, and I believe that variations like this are what was considered in the PEI referendum, and are also what is being considered in Québec. —DanielBrown
2010-02-11 16:47:23 City of Berkeley just adopted CV! 2/9/10
16. Council Findings for Ranked Choice Voting a. From: City Manager (PDF) Recommendation:
1 Adopt a Resolution finding that the conditions required by Charter Section 5(12) to implement ranked choice voting have been met.
2 Authorize the City Manager to execute a Memorandum of Understanding (MOU) with the Registrar of Voters (ROV).
Financial Implications: See report Contact: Deanna Despain, City Clerk, 981-6900 b. From: Councilmember Worthington (PDF) Recommendation: The Berkeley City Council move forward with the implementation and use of Instant-Runoff Voting. Financial Implications: Unknown Contact: Kriss Worthington, Councilmember, District 7, 981-7170 Action: 4 Speakers. M/S/C (Worthington/Anderson) to:
Adopt Resolution No. 64,770–N.S. finding that the conditions required by Charter Section 5(12) to implement ranked choice voting have been met.
Approve the City Manager’s recommendation to authorize the City manager to execute a Memorandum of Understanding (MOU) with the Registrar of Voters (ROV)
Approve Councilmember Worthington’s recommendation that the Berkeley City Council move forward with the implementation and use of Instant Runoff Voting.
Vote: Ayes: Maio, Moore, Anderson, Arreguin, Capitelli, Wengraf, Worthington, Bates. Noes: Wozniak. —MikeSiminitus
2010-11-11 18:55:39 STV has always bothered me, especially in multi-member districts. Where as in block voting you get one vote per seat that will be filled, in Choice Voting you only get one vote no matter how many seats are up for grabs. It seems to me that the ideal voting system in elections like the ASUCD senate or city council races would be some merger of the two where you get as many first place votes as number of seats available and then rank your candidates down from there. —DylanSchaefer
It's like n/n = 1. The "one vote" you get in STV is spread the same amount no matter who you vote for or who you are (roughly). The transfer property ensure this. So you'd have n/n = a/n + b/n + c/n = 1 with a+b+c adding up to n — and that division happens based on where your vote is most needed according to your preferences. This is a totally simplified explanation, but I hope it conveys that your vote isn't just "one vote" in a sad sort of way!
- sure, your voting power is still the same, but it seems that in effect you only get to vote on one of seats since you can only rank one candidate as #1. -DS
- That's not actually how it works, though :) Your vote continues to transfer even after your #1 is elected, and sticks around to help elect your #1 as long as it can. The "sticking around" helps ensure proportional representation.
- Not if the candidate doesn't reach the threshold, though.
- If the candidate doesn't reach the threshold then they're eliminated at some point and your vote will transfer to your next choice. The only case where this wouldn't really happen is if your first choice made it all the way to the final round before being eliminated, but in that case your other rankings really wouldn't have mattered much because all other candidates have been elected.
- But it does matter, since you have no say in who's elected to the other seats...
- In that exceptional case of your #1 choice getting knocked out in the final round, maybe. But it's exceedingly unlikely that the remaining votes for the second/third/etc choices in that pile would effect the election outcome. This property is known as monotonicity — and STV is non-monotonic. It's one of it's "flaws." However, all voting systems have a set of flaws. For instance, if STV was monotonic it would probably not give proportional results. In practice, this does not effect election outcomes.
1. Voting against your actual preferences to get your preferred candidates elected