Different uses for voting need different types of voting.
Enacting a Condorcet PolicyPairwise Tournament Voting, PTV, meets Condorcet’s criterion for a voting rule: If one option can win majorities over each of the others, then the voting rule should enact that option.
We can reuse our ballots from the IRV workshop to show the process of a round-robin tournament testing 1 against 1, each against each.
The teacher says, "Please stand over there if your ballot ranks A higher than B. If it ranks B higher, please stand here."
"Which option wins a majority?"
"Please stand there if your ballot ranks [the winner] higher than C. If it ranks C higher, please stand here."
"Which option wins a majority?"
We repeat this until 1 option has won majorities over each of the others. The tournament winner is usually the same as the IRV winner, but not always. The next section shows why.
For PTV we ask a series of questions similar to this:
For IRV we ask, "Please raise your hand if you are closer to B than to any other flag."
To compare IRV with PTV we ask, "Please raise your hand if you are closer to the Condorcet winner C than to the IRV winner D."
Both policy flags are both near our median voter. But 1 has a wide appeal and the other has a narrow centrist appeal.
Now, if this short ribbon reaches your desk, policy A reaches you with its narrow appeal. But if it does not reach you, policy B's wide appeal gets your vote. Which 1 wins?
PTV QuestionsDoes the tournament favor a narrowly-centrist policy? (No)
Does the median voter have the power to enact any policy? (No)
Can fringe voters influence the tournament result? (Yes)
Does the tournament use a “winning threshold”? (No)
Do votes “transfer”? (No)
Where could you use Pairwise Tournament Voting?
A well-cooked compromise should win the Condorcet tally. But the other dessert supreme should beat the compromise to become the IRV finalist versus chocolate.
A teacher is not likely to get these results simply by guessing the students' preferences. It's safer to hand out a homework ballot with many more options for students to rank, then select 3 or more options which produce different winners by IRV and Condorcet. For example:
Party Catering Selections
[If chocolate tends to get too many votes, it should be moved to fourth position on the ballot. The first, second and last options listed on any ballot tend to get more first-choice votes than they would if placed in the middle-ballot positions.]
The game is "cooked", but students won't feel herded if they are excited about the options.
PoliticalSim TM displays Excel charts of winners and losers and lets you change voting rules to compare their results. The charts for Condorcet and IRV could be improved. The Condorcet chart could show each 1 on 1 comparison, with a line drawn between the two, showing which voters are on which candidate's side. Users would click through the series of slides to see the whole Condorcet tally.
The IRV chart does let you click through the tally steps. Each step shows a candidate’s percentage of votes next to its symbol. Students can see who will be eliminated next and may guess, "Who will get those votes.?"
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