Presentation on theme: "1.4 Arrow’s Conditions and Approval Voting"— Presentation transcript:
1 1.4 Arrow’s Conditions and Approval Voting Ms. MagneDiscrete Math
2 Arrow’s ConditionsWe have talked about many different ways to rank voting preferences, but not all of them have been fair.Kenneth Arrow came up with 5 conditions that are necessary for a fair group ranking
3 Arrow’s Conditions1) Nondictatorship – one person’s votes should not be better then another person’s votes2) Individual Sovereignty – everyone shouldbe allowed to order their choices in anyorder they want3) Unanimity – if everyone prefers one choiceto another, then the group ranking shoulddo the same
4 Arrow’s Conditions4) Freedom from Irrelevant Alternatives – if a choice is removed, the order in which the others are ranked should not change5) Uniqueness of Group Ranking – Themethod of producing group ranking shouldgive same result whenever it is applied to agiven set of preferences. (not rolling a dice)
5 Approval VotingApproval Voting – voters are allowed to vote for as many or as few choices as they like, but they do not rank them. Winner is whoever has the most votes.
6 Approval VotingEx. Find the winner if everyone approves of their first and third choices.A B C DB C B BC D D CD A A ACThe Approval Winner is _____.
7 Approval Voting Ex. Use the Approval Method to find the winner. Voter 1Voter 2Voter 3Voter 4Voter 5AXBC