D has now gained a majority, and is declared the winner under IRV. This is similar to the idea of holding runoff elections, but since every voters order of preference is recorded on the ballot, the runoff can be computed without requiring a second costly election. There is still no choice with a majority, so we eliminate again. Candidate A wins under Plurality. Round 1: We make our first elimination. . The choice with the least first-place votes is then eliminated from the election, and any votes for that candidate are redistributed to the voters next choice. Bell System Technical Journal, 27(3), 379-423. Public Choice. As shown in Figure 5, the likelihood of winner concordance approaches one hundred% when one candidate achieves close to a majority of first-choice preferences. (Figures 1 - 4). Cambridge has used its own version for municipal elections since 1941, and across the U.S., it will be employed by more than a dozen cities by 2021 . \hline & 136 & 133 \\ \end{array}\), G has the fewest first-choice votes, so is eliminated first. This information may influence electoral policy decisions in the future as more states and municipalities consider different voting algorithms and their impacts on election outcome, candidate behavior, and voter enfranchisement. 1. A version of IRV is used by the International Olympic Committee to select host nations. Third, the Plurality algorithm may encourage infighting among candidates with otherwise common policy objectives and natural constituencies. Staff Tools| Contact Us| Privacy Policy| Terms | Disclosures. It is so common that, to many voters, it is synonymous with the very concept of an election (Richie, 2004). This frees voters from having to guess the behavior of other voters and might encourage candidates with similar natural constituencies to work with rather than against each other. Still no majority, so we eliminate again. In order to account for and remedy this issue, we uniformly divide the range of the possible values of entropy and HHI into 100 equal segments (hereafter referred to as bins), and then calculate the average concordance of all elections with entropy or HHI within those bins. Instant runoff voting is similar to a traditional runoff election, but better. In this study, we evaluate the outcomes of a 3-candidate election. \end{array}\). But while it's sometimes referred to as "instant runoff" voting, the primary vote count in New York will be. However, to our knowledge, no studies have focused on the impact of ballot dispersion on Plurality and IRV election outcomes. This is similar to the idea of holding runoff elections, but since every voters order of preference is recorded on the ballot, the runoff can be computed without requiring a second costly election. In this re-vote, Brown will be eliminated in the first round, having the fewest first-place votes. \hline 2^{\text {nd }} \text { choice } & \mathrm{C} & \mathrm{A} & \mathrm{D} & \mathrm{C} & \mathrm{E} & \mathrm{A} \\ CONs of IRV/RCV It is new - A certain percentage of people don't like change. \end{array}\). Find the winner using IRV. \hline 3^{\text {rd }} \text { choice } & \mathrm{D} & \mathrm{B} & \mathrm{C} & \mathrm{E} & \mathrm{C} & \mathrm{B} \\ \hline 1^{\text {st }} \text { choice } & \text { B } & \text { D } \\ So it may be complicated to, If you look over the list of pros above you can see why towns that use IRV tend to have better voter turnout than before they started the IRV. Round 1: We make our first elimination. Note that even though the criterion is violated in this particular election, it does not mean that IRV always violates the criterion; just that IRV has the potential to violate the criterion in certain elections. Round 2: We make our second elimination. In this election, Carter would be eliminated in the first round, and Adams would be the winner with 66 votes to 34 for Brown. This voting method is used in several political elections around the world, including election of members of the Australian House of Representatives, and was used for county positions in Pierce County, Washington until it was eliminated by voters in 2009. The results show that in a 3 candidate election, an increase in the concentration of votes causes an increase in the concordance of the election algorithms. Burnett, C. M. and Kogan, V. (2015). "We've had a plurality in general elections for quite some time. It is used in many elections, including the city elections in Berkeley, California and Cambridge, Massachusetts, the state elections in Maine, and the presidential caucuses in Nevada. \hline 1^{\text {st }} \text { choice } & \mathrm{B} & \mathrm{C} & \mathrm{B} & \mathrm{D} & \mathrm{B} & \mathrm{E} \\ These situations are extremely uncommon in a two-party system, where the third-party candidate generally garners little support. The relationship between ballot concentration and winner concordance can be observed even in the absence of full voter preference information. If no candidate has has more than 50% of the votes, a second round of plurality voting occurs with All of the data simulated agreed with this fact. The Plurality algorithm, though extremely common, suffers from several major disadvantages (Richie, 2004). Consider the preference schedule below, in which a companys advertising team is voting on five different advertising slogans, called A, B, C, D, and E here for simplicity. On the other hand, the temptation has been removed for Dons supporters to vote for Key; they now know their vote will be transferred to Key, not simply discarded. In this election, Carter would be eliminated in the first round, and Adams would be the winner with 66 votes to 34 for Brown. -Plurality Elections or Instant Runoff Voting? - A certain percentage of people dont like change. Second, it encourages voters to think strategically about their votes, since voting for a candidate without adequate support might have the unintended effect of helping a less desired candidate win. Consider again the election from Try it Now 1. W: 37+9=46. For example, consider the algorithm for Instant-Runoff Voting shown in Table 2, and the series of ballots shown in Table 3. The 44 voters who listed M as the second choice go to McCarthy. If no candidate has a majority of first preferences, the least popular candidate is eliminated and their votes. In IRV, voting is done with preference ballots, and a preference schedule is generated. If one of the candidates has more than 50% of the votes, that candidate wins. D has now gained a majority, and is declared the winner under IRV. Australia requires that voters, dont want some of the candidates. https://youtu.be/C-X-6Lo_xUQ?list=PL1F887D3B8BF7C297, https://youtu.be/BCRaYCU28Ro?list=PL1F887D3B8BF7C297, https://youtu.be/NH78zNXHKUs?list=PL1F887D3B8BF7C297, Determine the winner of an election using preference ballots, Evaluate the fairnessof an election using preference ballots, Determine the winner of an election using the Instant Runoff method, Evaluate the fairnessof an Instant Runoff election, Determine the winner of an election using a Borda count, Evaluate the fairness of an election determined using a Borda count, Determine the winner of en election using Copelands method, Evaluate the fairness of an election determined by Copelands method. The LWVVT has a position in support of Instant Runoff Voting, but we here present a review ofthe arguments for and against it. \hline 2^{\text {nd }} \text { choice } & \mathrm{C} & \mathrm{D} & \mathrm{D} & \mathrm{C} & \mathrm{E} & \mathrm{D} \\ Higher degrees of voter preference concentration, or lower Shannon entropy, tends to increase the potential for winner concordance. After transferring votes, we find that Carter will win this election with 51 votes to Adams 49 votes! Its also known as winning by a relative majority when the winning candidate receives the highest . With primaries, the idea is that there is so much publicity that voters in later primaries, and then in the general election, will have learned the candidates weaknesses and be better informed before voting. Of these alternative algorithms, we choose to focus on the Instant-Runoff Voting algorithm (IRV). Instant Runoff Voting (IRV), also called Plurality with Elimination, is a modification of the plurality method that attempts to address the issue of insincere voting. Saves money compared to running primary elections (to narrow the field before the general election) or run-off elections (to chose a final winner after a general election, if no candidate has a majority, and if the law requires a majority for that office). Let x denote a discrete random variable with possible values x1 xn , and P(x) denote the probability mass function of x. Still no majority, so we eliminate again. With IRV, the result can beobtained with one ballot. Kilgour, D. M., Grgoire, J. and Foley, A. M. (2019) The prevalence and consequences of ballot truncation in ranked-choice elections. A ranked-choice voting system (RCV) is an electoral system in which voters rank candidates by preference on their ballots. Available:www.doi.org/10.1016/j.electstud.2016.02.009. 1998-2021 Journal of Young Investigators. \hline Round 3: We make our third elimination. Accessibility StatementFor more information contact us atinfo@libretexts.orgor check out our status page at https://status.libretexts.org. Find the winner using IRV. C has the fewest votes. For our analysis, we employ a stochastic Monte Carlo simulation of hypothetical 3 candidate elections. \hline 5^{\text {th }} \text { choice } & \mathrm{E} & \mathrm{E} & \mathrm{E} & \mathrm{B} & \mathrm{D} & \mathrm{C} \\ A version of IRV is used by the International Olympic Committee to select host nations. Both of these measurements share the same cutoff for guaranteed concordance as their corresponding ballot concentration counterparts. Writing this paper would not have been possible without help from Middlesex Community College Professors Scott Higinbotham and Aisha Arroyo who provided me with critical guidance in the direction and methodologies of this paper. However, under Instant-Runoff Voting, Candidate B is eliminated in the first round, and Candidate C gains 125 more votes than Candidate A. The last video shows the example from above where the monotonicity criterion is violated. This study seeks to determine the behavior and rate of change in algorithmic concordance with respect to ballot dispersion for the purpose of understanding the fundamental differences between the Plurality and Instant-Runoff Voting algorithms. \hline & 3 & 4 & 4 & 6 & 2 & 1 \\ In order to utilize a finer bin size without having bins that receive no data, the sample size would need to be drastically increased, likely requiring a different methodology for obtaining and storing data and/or more robust modeling. C has the fewest votes. 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