2017.04.06 how should we elect our leaders
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Dr Ashley Piggins, Economics, gave this talk entitled "How should we elect our leaders?" on behalf of the Group Decision Making research cluster as part of the 2017 Whitaker Institute Research Day on the 6th of April 2017 at NUI Galway.
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2017.04.06 how should we elect our leaders
- 1. How Should We Elect Our Leaders? Ashley Piggins Group Decision Making Whitaker Institute Research Day, 6th April 2017
- 6. Part 1: Trump v Clinton Clinton approx. 3 million more votes than Trump.
- 7. Part 2: Brexit • Statistically correct interpretation of the vote data is a tie. • 72% turnout so only 37% eligible voters wanted Leave. • Misleading to claim that “The people of the United Kingdom voted to leave the European Union” as this suggests the whole population voted. • Need inference from subset to whole. • Simple extrapolation fails due to regional heterogeneity of the data.
- 10. Part 3: FPTP with Run-off 82.2% 17.8%
- 11. Democratic “Misfires” blamed on Populism • Trump, Brexit, Le Pen … immigration, globalisation, nationalism. • Other “populists” like Evo Morales in Bolivia and Rodrigo Duterte in Philippines are quite different. • Populism not a coherent political philosophy. • Ordinary people rebelling against an elite. • Compatible with racism, socialism, economic nationalism, militarism, multi-culturalism, etc. • Undoubtedly true that Populism contributes to misfires.
- 12. More Fundamental Problem • Every country has to devise a solution to a mathematical problem in order to operate at all. • This mathematics is hidden from view, subtle, and almost never discussed. • Yet it explains “misfires” better than Populism. • Bad mathematics, not bad voters, leads to misfires.
- 16. Example: FPTP Voting 32.5% 32.5% 35% Centre-Left Centre-Right Le Pen Centre-Right Centre-Left Centre-Right Le Pen Le Pen Centre-Left
- 17. Example: FPTP Voting 32.5% 32.5% 35% Centre-Left Centre-Right Le Pen Centre-Right Centre-Left Centre-Right Le Pen Le Pen Centre-Left Le Pen wins even though 65% thought she was the worst candidate. Centre-Left and Centre-Right act as “spoilers” for one another.
- 18. Another Example 48.85% 48.84% 2.31% B G N G N G N B B
- 19. Another Example 48.85% 48.84% 2.31% B G N G N G N B B
- 20. Lost Information The voting rule “loses” all information bar the top-ranked candidate. 48.85% 48.84% 2.31% Bush Gore Nader Gore Nader Gore Nader Bush Bush
- 21. Lost Information The voting rule “loses” all information bar the top-ranked candidate. A good voting rule elicits all ranking information and uses it. 48.85% 48.84% 2.31% Bush Gore Nader Gore Nader Gore Nader Bush Bush
- 22. Condorcet Winner LOOK AT EVERY PAIR 48.85% 48.84% 2.31% B G N G N G N B B
- 23. Condorcet Winner Gore BEATS Nader 48.85% 48.84% 2.31% Bush G N G N G N Bush Bush
- 24. Condorcet Winner Nader BEATS Bush 48.85% 48.84% 2.31% B Gore N Gore N Gore N B B
- 25. Condorcet Winner Gore BEATS Bush 48.85% 48.84% 2.31% B G Nader G Nader G Nader B B
- 26. Condorcet Winner Gore BEATS Nader BEATS Bush 48.85% 48.84% 2.31% B G N G N G N B B
- 27. Maskin’s Dominance Theorem • We can list the desirable properties we want a voting rule to satisfy. • No voting rule can ever be found that satisfies all of them (Arrow). • Maskin proves that Condorcet’s method satisfies these conditions more often than any other rule. • In this sense it “dominates” (i.e. is better) than all other rules.
- 28. Trump • Republican state primaries decided by FPTP rule, not Condorcet’s method. Easy for the GOP to change. • Anti-Trump vote split by “spoilers”: Cruz, Rubio, Jeb Bush, Kasich, and others. • In the first 17 primaries won by Trump he never got a majority of votes. Early victories gave him momentum. • Condorcet winner would have been Cruz or Rubio. • His election was a fluke.
- 30. Approval Voting A B C D E Voter 1 X X Voter 2 X X Voter 3 X X Voter 4 X X Votes 1 1 3 2 1 If there are two seats then C and D are elected.
- 31. Conclusion • Bad electoral systems contribute greatly to misfires. • This is under-appreciated. • FPTP particularly flawed. • Theoretical justification exists for Condorcet’s method. • Should apply “supermajority” to referenda, e.g. 60% threshold.
Editor's Notes
- Flaw of Plurality
- Flaw of Plurality
- This is a Condorcet method!