Comparing RCV and STAR Voting

Traditional Ranked Choice or Version 2.0?

Traditional Instant Runoff Voting (IRV) is the Ranked Choice O.G. - it's been used around the world and the states for more than a century. STAR Voting (Score Then Automatic Runoff) is a modern preference voting method that was invented to go further to deliver on the original goals, while addressing known issues with the old method.

RCV and STAR have a lot in common:  Only one election is needed, primaries are optional, voters have more voice. Both are user friendly. Both can be used for single winner, multi-winner, or proportional representation elections ...

… That said, there are significant differences. 

Technically "Ranked Choice Voting" or RCV is an umbrella term for any number of ranked ballot voting methods, however in practice RCV is Instant Runoff Voting, the method discussed below.

 

The U.S. Supreme Court has found unequivocally that 'One Person, One Vote' requires that "each vote be given as much weight as any other vote." Put simply, our very notion of democracy requires that the voters and the candidates are on an even playing field in every election, and every proposed reform should be scrutinized through this lens.

  • STAR Voting provides equality to voters. In STAR Voting voters are able to weigh in on as many candidates as they want, at any level they want, and all that data is counted. This is the key to passing the test of balance and the Equality Criterion. Moreover, not matter who the finalists end up being, the STAR Voting runoff ensures that your full vote goes to the finalist you prefer. The runoff is the key to ensuring that a voting system gives you an equally weighted vote, whether your favorite can win or not. With STAR Voting, every possible vote in both the scoring and automatic runoff stages has an equal, and opposite vote that could be cast. In order for a voting method to not split the vote, it needs to pass the test of balance. 

  • IRV fails 'One Person, One Vote.' IRV, by its very design, gives some voters more than one bite at the apple while giving others just one. In IRV, second choice votes only ever count for those voters who happen to see their first choice eliminated before their second choice. Whether you pick a strong consensus candidate or a weak extremist second, if your first choice hangs around in the count longer, your second choice is never considered by IRV. The 2009 Mayoral IRV election in Burlington, Vermont is a real-world example of how IRV's failure to provide an equal vote can result in an obviously non-representative outcome and subsequent repeal of the system.

Does the voting method eliminate vote splitting and spoilers? 

Vote Splitting is one way that voting methods can leave voters divided and conquered, even when they had a majority.
  • RCV: In voting methods like Choose-One Plurality and in RCV, coalitions of voters who have more candidates on their side have a mathematically less powerful vote than voters who only support one candidate. RCV mitigates it, but vote splitting can still happen in every round.  
  • STAR: Voting methods like STAR Voting, Score Voting, and Approval Voting allow voters to show full support for multiple candidates. This ensures that an equally weighted vote is always possible, which in turn eliminates vote-splitting and the Spoiler Effect in the vote itself. 


Honesty:

Can voters safely express their honest opinion on the ballot? Do voters need to vote strategically in order to not waste their vote?


Voters in RCV can't always safely vote 1st choice for their honest favorites

Ranked Choice proponents often make the inaccurate claim that “With RCV, voters can honestly rank candidates in order of choice. Voters know that if their first choice doesn’t win, their vote automatically counts for their next choice instead. This frees voters from worrying about how others will vote and which candidates are more or less likely to win.” In fact, you can only safely rank candidates honestly in RCV if your favorite either has no chance at all or is a very strong candidate because there is no guarantee that if your favorite is eliminated your next choice will actually be counted. This video and this video show clearly how RCV suffers from a type of vote-splitting called the center-squeeze spoiler effect:

 

 

Because RCV doesn't eliminate the spoiler effect, major parties can honestly propagandize against supporting up-and-coming third party candidates, as they do in Australia: "This confusion is often encouraged by the major parties who do not want people to give a first preference to a minor party. In left-wing inner-city seats around Sydney and Melbourne, where the Greens are now challenging the hold of the Labor Party, Labor campaigners often will claim that a vote for the Greens would help the Liberal Party, sowing confusion about our electoral system, in order to bring progressive voters back to Labor."

Plain Score Voting has potential strategic issues

IRV advocates argue that rating systems are vulnerable to tactical 'bullet voting' - that is, support of just one candidate on the ballot in order to maximize the chance of one's favorite choice winning. Rating advocates have demonstrated that in a significant number of IRV elections, giving full support to your favorite can actually help elect your least favorite candidate.

STAR Voting breaks the tradeoff

STAR's scoring phase ensures that the two strongest candidates overall advance to the final runoff, and the runoff phase reduces the incentive to score second choices tactically. With STAR Voting, you can honestly support your true favorite and second choice without worrying you'll be promoting a losing candidate over a stronger consensus choice or unduly harming your favorite's chance of winning.



Accuracy:

How accurately does the voting system reflect the will of the people?

Voter Satisfaction Efficiency models representation accuracy

Voting method simulation is used primarily to determine how accurately a voting method will produce an outcome that represents the will of the electorate. In a real human election it's hard to actually know what the voters really wanted - they could have been voting strategically, exit polling is imprecise and so on. By running simulated voters through thousands or millions of simulated elections, voting systems can be concretely evaluated and compared.

 

 

STAR Voting tops the list

STAR Voting simulates best-in-class in the several election method simulators that have included it. Across the board, with both honest voters and mixtures of strategic voters, STAR is "unquestionably a top-shelf method."

IRV offers middle-of-the-road representation accuracy

Traditional IRV, by contrast, doesn't come close to the top of the list. Recent work by Robert Norman, a mathematician at Dartmouth, suggests that IRV's topsy-turvy math issues would create non-representative outcomes in one in five close contests among three candidates and that with larger numbers of candidates, it would happen even more often.

Burlington demonstrates IRV's counting failure with crystal clarity: Three strong candidates faced off - we'll call them A, B and C. A majority of voters expressed a preference for A over B, and a plurality of voters expressed a preference for A over C, yet the IRV count eliminated A before either B or C, and elected a candidate not supported by the majority. Not surprisingly, Burlington repealed IRV the next year.



Simplicity:

How easy is the system for voters to understand and cast ballots, and how easy is it for elections officials to tabulate and hand-recount?

 

The Ballots

For a small number of candidate choices, it's arguable whether scoring or rank ordering is simpler: if you only want to support one, bubbling in "first choice" or "top score" are essentially equivalent.

As the number of candidates and choices increase, however, scoring clearly becomes by the simpler method, because each candidate can be considered individually, where ranking systems essentially require the voter to sort the candidates before filling out the ballot. As a Wikimedia board member stated:

"I actually voted in an election conducted under a Condorcet method (specifically Schulze's beatpath method): the Wikimedia board election. There were more than a dozen candidates, and about the only way I could vote intelligently was to first rate them, then turn that into a ranked ballot. So obviously a rating-type ballot (where the second step was not needed) would be easier and quicker to cast."

Multi-round elimination is complex

The mechanism for tabulating RCV can remain opaque even for sophisticated voters. Steve Pond wrote the following about RCV after its adoption as the voting system for choosing Best Picture by the Motion Picture Academy: "A year and a half after the Academy went to a different system for counting Best Picture ballots, nominees and voters and campaigners still don't understand how it works. And it's driving me crazy."

Because RCV's counting algorithm goes through one round for each losing candidate until a winner is decided, elections can take many rounds to compute. The image below represents a sample election vote tally in the multi-round RCV process. It's hard for observers and lay voters to draw meaningful conclusions about voter preferences from these intermediate results:

svi_irv_results.png

 

STAR Voting always completes in two rounds

STAR Voting is simple to tabulate, with transparent results that show overall popular support for every candidate. You can see the election results of the sample election run with STAR below:

svi_star_results.png

 

RCV requires centralized counting

The winner of an RCV election cannot be tabulated until all ballot information is reported to a central location. Maine, which adopted RCV for some elections in 2018, is dealing with the headaches of this system. "Ballots would have to be shipped by town clerks to a central location in Augusta for additional voting rounds. Thus the outcome of an election in a multiple-candidate race might not be known for several weeks."

We think it's likely that modern elections offices would use the internet to transfer election data from the counties to the state HQ, so we expect it wouldn't take weeks, but regardless, the lack of precinct summability is a real weakness of RCV. Each locale has to come up with all of the many possible combinations of rank orderings and report the total for each, in order that the central counting authority can begin the process to determine the winner. These partial results give little meaningful information to the voters. A small subset of one election's partial results in RCV might look like this:

svi_irv_presum.png

 

STAR Voting results can be summed by precinct

STAR Voting gives information that is useful in understanding how the local electorate felt about the election and makes the results easier to verify by hand-recount. Each precinct sums the scores for each candidate and creates a preference matrix tallying how many ballots prefer each candidate to each other candidate in the race. The central election authority adds up all the precinct sums and all of the precinct preference matrices. The final winner is determined by looking up the two top scoring candidates in the final preference matrix to see which one more voters preferred.

svi_star_presum.png

Reading the preference matrix: each element in the matrix represents the voter preferences of one candidate over another. So the highlighted number "15" in the second column of the first row means that 15 voters gave A ("A>" row label) a higher score than B (column label). The highlighted 10 in the first column of the second row means that 10 voters gave B a higher score than A. The head-to-head total is A:15 to B:10.


Expressiveness: Can the voter express a nuanced opinion on the outcome?


Ranking is more expressive than plurality

Our current voting system, where we are limited to picking a single favorite in each election, is the least expressive voting system humans have ever constructed. Ranked Choice Voting allows the voter to express an opinion on multiple candidates by placing them in preference order.

Preference order alone leaves out information

The same ordering A > B > C could mean that the voter thinks any of the following:

  • A is an awesome candidate, B is mediocre and C is the devil incarnate
  • A is awesome, B is almost as awesome, and C is just a hair less awesome than A and B
  • A is above average, B is mediocre, and C is mediocre and dishonest

Furthermore while RCV lets you express support for more than one candidate, it doesn't actually count that secondary support at all until your first choice candidate is eliminated and even then it's not guaranteed. For some voters your first choice can be eliminated and your next choices will not be counted. This is known as an "exhausted ballot", meaning that these ballots are not counted in the final round which determines the winner. The more viable candidates are in the race the more likely this is to happen, and the phenomena predictably puts voters who prefer a strong underdog at a disadvantage.

Scoring is more expressive than ranking

Instead of only counting the voter's support for one candidate at a time, STAR allows the voter to express, and counts, a nuanced level of support for any number of candidates on the ballot.

It's Time For 2.0

The need for true election reform is more apparent now than ever before, and the recent adoption of RCV in Benton County, OR and the state of Maine show that electorates on both coasts are ready for more expressive voting systems. What we need now is the upgraded version, that actually gets rid of the spoiler effect, once and for all, and isn't vulnerable to repeal after adoption due to complexity of implementation and non-representative outcomes.

The American electorate is hungry for a real solution to our broken political system. We clearly need an election system that gives us all an equal say, accurately reflects our collective will in the outcome, is simple for us to ballot and for election officials to tabulate, and that allows us to expressively share our honest opinions on the outcome. By all these measures, the new Ranked Choice - STAR Voting - is the clear winner.

 

 

Sources:

1.) “[IRV] can cause spoilers in up to 1 in 5 elections or worse when there are more candidates according to expert analysis.” Frequency of monotonicity failure under Instant Runoff Voting: Estimates based on a spatial model of elections. By Joseph T Ornstein, University of Michigan, Dept. of Political Science and Robert Z. Norman, Dartmouth College, Dept. of Mathematics, 2013. 

2.) "The rate of ballot exhaustion was high in each election, ranging 9.6%–27.1%." Ballot (and voter) “exhaustion” under Instant Runoff Voting: An examination of four ranked-choice elections. By Craig M. Burnett, University of North Carolina, and Vladimir Kogan, Ohio State University, USA. 2015.

3.) "We find that RCV helps reduce the substantial drop in voter participation that commonly occurs between primary and runoff elections. Otherwise RCV does not appear to have a strong impact on voter turnout and ballot completion. In a case study of Minneapolis we find similar levels of socioeconomic and racial disparities in voter participation in plurality and RCV elections." Voter Participation with Ranked Choice Voting in the United States. By David C. Kimball and Joseph Anthony, Department of Political Science University of Missouri‐St. Louis St. Louis, MO. 2016.

4. "Drawing on previous research conducted by the Maine Policy Institute, McCarty examined 98 RCV elections from 2006 to 2019 and found that, on average, 10.8 percent of ballots casted were considered exhausted by the final round." Expert report reveals weaknesses of RCV. By Isabelle Christie. 2020

5. "Concerns about the fairness of IRV led at least four jurisdictions to repeal... Burlington, VT (2006–2009), Cary, NC (2007–2009), Pierce County, WA (2006–2009), Aspen, CO (2009)." and "Consistently, precincts where more African-Americans reside are more likely to collect overvoted, voided ballots. And this often occurs where more Latino, elderly, foreign-born, and less wealthy folks live." Overvoting and the Equality of Voice under Instant-Runoff Voting in San Francisco, California Journal of Politics and Policy. By Francis Neely and Jason A. McDaniel San Francisco State University. 

6.) Voter Satisfaction Efficiency (VSE) studies by Dr Jameson Quinn Phd. At the time this study was released Quinn was Vice Chair for the Center for Election Science. Quinn is now on the board of the Equal Vote Coalition http://electionscience.github.io/vse-sim/vse.html

7.) Election Accuracy. A comprehensive list and overview of studies, sources, and citations comparing voting methods including RCV and STAR. http://starvoting.us/accuracy