2. Plurality, Instant Runoff, and Hare Section 1.2

3. 1.2 Plurality, IRV, and Hare 2 Who should win? 10951 ABCD DCBC CDDA BAAB 1.A 2.B 3.C 4.D

4. 1.2 Plurality, IRV, and Hare 3 Ideas 10951 ABCD DCBC CDDA BAAB

5. 1.2 Plurality, IRV, and Hare 4 Plurality Most Votes Wins Voting Method 1

6. 1.2 Plurality, IRV, and Hare 5 “Plurality” = More votes than anyone else Plurality is the only voting method that may elect someone disliked by of the voters Plurality Winner is. (Simply look along the top row) 353332 ACB BBC CAA Is there a majority winner?

7. 1.2 Plurality, IRV, and Hare 6 Who wins using Plurality? 1. A 2. B 3. C 4. D 5. E 111 ACE BBC CAB 111 DBB BAC CCA 111 DCB BBC CAA 11 EA BB AE DDC EED EEE ADD ADE EED DC CD

8. 1.2 Plurality, IRV, and Hare 7 Plurality is also known as “Winner-Take-All” In presidential elections all the electoral votes in 48/50 states are awarded to the Plurality winner “Chads”

9. 1.2 Plurality, IRV, and Hare 8 Which is correct? 1. If you have a majority of the votes then you have a plurality 2. If you have a plurality then you have a majority of the votes 3. Both statements are true 4. Both statements are false

10. 1.2 Plurality, IRV, and Hare 9 Who wins using Plurality? 1. A 2. B 3. C 4. D 8964 BACC CDBD ACAB DBDA An extreme case

11. 1.2 Plurality, IRV, and Hare 10 Plurality High School Class Rank A school ranks its students by the number of A’s they receive Who would be ranked higher? Hortense: Hildegard:

12. 1.2 Plurality, IRV, and Hare 11 Plurality - For Better or Worse Most researchers believe that Plurality does the. job of picking a winner It is still widely used for important elections in the United States, Canada, the United Kingdom, and India And by the faculty in our College of Arts and Sciences

13. 1.2 Plurality, IRV, and Hare 12 Plurality - Advantages 1.Easy to 2.Easy to

14. 1.2 Plurality, IRV, and Hare 13 Plurality - Disadvantages Why bother? My guy (C) hasn’t got a chance. I’m outta here 873 BAC CCA ABB 1. Sm Cli 2. Vo Ap

15. 1.2 Plurality, IRV, and Hare 14 First disadvantage is the big problem with Plurality. How can we prevent a small clique from winning? Animation 1.Keep having elections until someone gets a majority 2.Reduce the field to 2 candidates 3.You can’t prevent it 4.Other

16. 1.2 Plurality, IRV, and Hare 15 Animation showed Traditional Runoff Election Very common - Two separate elections separated by weeks/months Drawbacks Expensive Longer campaigns Different voting group for 2 nd election

17. 1.2 Plurality, IRV, and Hare 16 How could we conduct a Runoff “instantly” - using only this preference schedule? 20191510 ABCD DDBC CCDB BAAA

18. 1.2 Plurality, IRV, and Hare 17 Instant Runoff Voting (IRV) Algorithm all candidates... “Re-tally” the. The candidate with votes wins Voting Method 2

19. 1.2 Plurality, IRV, and Hare 18 What is an “algorithm”? Arabic for “calculate” Definition: A precise set of rules specifying how to solve some problem Examples –Divide 232 by 17 –Shampoo

20. 1.2 Plurality, IRV, and Hare 19 1594 ABC BEE CAB 32 DE BA CC DDA ECD EB AD First Tally Re-Tally Eliminate wins to. Animation of the IRV algorithm

21. 1.2 Plurality, IRV, and Hare 20 Who wins using IRV ( and how many votes did the winner get?) 10755 BDCA ACAC DADD CBBB 1. A – 10 2. A – 15 3. B – 10 4. B – 12 5. C – 10 6. C – 15 7. D – 12 8. D – 17

22. 1.2 Plurality, IRV, and Hare 21 Different voting methods can produce different winners in the same election 1.True 2.False

23. 1.2 Plurality, IRV, and Hare 22 Important Theme #1 IRV winner. Plurality winner. 10755 BDCA ACAC DADD CBBB

24. 1.2 Plurality, IRV, and Hare 23 If candidate A has a majority of the first- place votes, A will always win using IRV 1. True 2. False 3. Can’t tell

25. 1.2 Plurality, IRV, and Hare 24 Instant Runoff - Advantages 100983 ABC BCB CAA 1.Ma W 2.Ch er 3. L L P 4.Fewer Per Att 5.

26. 1.2 Plurality, IRV, and Hare 25 Which candidate has a legitimate complaint with IRV? 10098972 ABCD CCAC DDDA BABB 1. A 2. B 3. C 4. D 5. No one

27. 1.2 Plurality, IRV, and Hare 26 IRV – Disadvantage 1. French Presidential Election - 2002 Election

28. 1.2 Plurality, IRV, and Hare 27 How to prevent strong 3 rd, 4 th, … place candidates from being eliminated in the first round? 1.Eliminate all but the top 3 vote getters and re-tally 2.Eliminate all but the top 4 vote getters and re-tally 3.Eliminate the lowest vote getter. Re- tally. Again, eliminate lowest vote- getter. Re-tally. Etc. etc. 4.You can’t prevent it

29. 1.2 Plurality, IRV, and Hare 28 http://video.google.com/videoplay?docid=13853515 42097864075&q=musical+chairs&hl=en

30. 1.2 Plurality, IRV, and Hare 29 The video hints at a new voting method. Explain how it works with this preference schedule 20191510 ABCD DDBC CCDB BAAA

31. 1.2 Plurality, IRV, and Hare 30 Hare Algorithm the. Re-tally the. Repeat this process, each time eliminating the. Eventually there will be only. The one with the wins Voting Method 3

32. 1.2 Plurality, IRV, and Hare 31 Animation using Hare 896 BAC CDB ACA 3 D C B DBD A Tally 1 Re-Tally wins to.

33. 1.2 Plurality, IRV, and Hare 32 Who wins using Hare? ( and determine how many votes the winner gets) 1712616 ABCD CCAC DDBA BADB 1. A – 23 2. A – 35 3. B – 18 4. B – 35 5. C – 34 6. C – 37 7. D – 28 8. D – 45

34. 1.2 Plurality, IRV, and Hare 33 If there are 3 candidates IRV and Hare 1. Always choose the same winner 2. Never choose the same winner 3. Sometimes choose the same winner 4. Can’t tell

35. 1.2 Plurality, IRV, and Hare 34 If A has a majority of the first-place votes, A will always win using Hare 1. True 2. False 3. Can’t tell

36. 1.2 Plurality, IRV, and Hare 35 Hare Method – Advantages 1.M W 2.Co ve 3.Fewer P A 4.En V T

37. 1.2 Plurality, IRV, and Hare 36 Hare Method – Disadvantages 1. D to E

38. 1.2 Plurality, IRV, and Hare 37 Who wins using Plurality? 1. A 2. B 3. C 4. D 20191510 ABCD DDBC CCDB BAAA

39. 1.2 Plurality, IRV, and Hare 38 Who wins using IRV? 1. A 2. B 3. C 4. D 20191510 ABCD DDBC CCDB BAAA

40. 1.2 Plurality, IRV, and Hare 39 Who wins using Hare? 1. A 2. B 3. C 4. D 20191510 ABCD DDBC CCDB BAAA

41. 1.2 Plurality, IRV, and Hare 40 OK, who wins? ( Sorry, no questions on this one) 1. A 2. B 3. C 4. I don’t know 353332 ACB BBC CAA

42. 1.2 Plurality, IRV, and Hare 41 If you wanted candidate A to win which voting method would you choose? 17192110 ABCD DDBA CAAB BCDC 1.Plurality 2.Run off 3.Hare

43. 1.2 Plurality, IRV, and Hare 42 If you wanted candidate B to win which voting method would you choose? 17192110 ABCD DDBA CAAB BCDC 1.Plurality 2.Run off 3.Hare

44. 1.2 Plurality, IRV, and Hare 43 If you wanted candidate C to win which voting method would you choose? 17192110 ABCD DDBA CAAB BCDC 1.Plurality 2.Run off 3.Hare

45. End of 1.2

46. 1.2 Plurality, IRV, and Hare 45 2000 Presidential Election Florida’s Famous “Hanging Chads ” 1.Bush defeats Gore by 537 votes (out of 5,800,000 cast) 2.Wins ALL electoral votes in the state 3.Bush becomes President

47. 1.2 Plurality, IRV, and Hare 46 Plurality - An Extreme Case Mapai Ahdut Ha'avodah Aguddat Israel Arab Democratic Party Arab Movement for Change Ariel Sharon Forms New Political Party The Center Party Centrist Party Takes Shape Citizen's Rights Movement Degel Hattorah Democratic Choice Democratic Movement for Change Gahal General Zionists/Liberal Party Gesher Hadash Herut The Israeli Communist Party Kach Kadima The Labor Party United Arab List United Torah Judaism The Likud Party

48. 1.2 Plurality, IRV, and Hare 47 Election 1 A 10 9 BC 4 D 3 E 2 Election 2

49. 1.2 Plurality, IRV, and Hare 48 CandidatesVotes 1st round %Votes 2nd round% Jacques Chirac 5,665,85519.88%25,537,95682.21% Jean-Marie Le Pen 4,804,71316.86%5,525,03217.79% Lionel Jospin4,610,11316.18% François Bayrou 1,949,1706.84% Arlette Laguiller 1,630,0455.72% Jean-Pierre Chevènem ent 1,518,5285.33% Noël Mamère Olivier Besancen ot French Presidential Election 2002

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