# Shared Flashcard Set

## Details

Voting and Social Choice
Vocabulary
21
Mathematics
02/17/2016

Term
 Social Choice
Definition
 How groups can best arrive at decisions.
Term
 Preference List Ballot
Definition
 A Ballot that ranks the candidates from most preferred to least preferred. (with no ties)
Term
 Majority Rule
Definition
 A voting system for elections with two candidates in which the candidate with the most votes wins.
Term
 Dictatorship
Definition
 All ballots are ignored except that of the dictator.
Term
 Imposed Rule
Definition
 Candidate "X" wins regardless of who votes for him. (predetermined)
Term
 Minority Rule
Definition
 The candidate with the fewest votes wins.
Term
 Monotone
Definition
 If a new election were held and a single voter changes his vote from being a vote for the loser to a winner, then the outcome remains the same.
Term
 Condorcet's Method
Definition
 A candidate is the winner when he would defeat ever other candidate in a one-to-one contest using majority rule.
Term
Definition
 There are elections in which Condercet's Method yields no winner.
Term
 Plurality Voting
Definition
 Candidate with the most 1st place votes wins. (does not require the winner to have a majority.)
Term
 Condorcet's Winner Criterion
Definition
 For every possible sequence of preference list ballots:1. There is no Condorcet winner.2. The voting system produces the same winner as Condorcet's Method.
Term
 Manipulability
Definition
 A voter's advantage to submit a ballot that misrepresents his true preference.
Term
 Borda Count
Definition
 A rank method of voting that assigns points in a non increasing manner to each candidate and then sums these points to arrive at the groups final rankings.
Term
 Borda Score
Definition
 Total points of each candidate. (highest score wins)
Term
 Independence of Irrelevant Alternatives
Definition
 It is impossible for an alternative B to move from non winner to winner status unless at least one voter reuses the order in which had B and the winner ranked.
Term
 Agenda
Definition
 An ordering of the candidates to be considered (horizontal)
Term
 Sequential Pairwise Voting
Definition
 Pits the 1st candidate against the second in a one-to-one contest. The winner confronts the 3rd candidate while the loser is eliminated. Continue through the agenda until one candidate remains.
Term
 Pareto Condition
Definition
 If all voters prefer one candidate A to another B, then candidate B cannot be the winner. (Sequential Pairwise does not satisfy this)
Term
 Hare System
Definition
 The winner is determined by repeatedly deleting alternatives that are least preferred. (**Rounds**)
Term
 Plurality With Runoff
Definition
 There is a plurality election, then (if needed) there is a runoff (new election) between the two candidates receiving the most first place votes. (winner has majority of votes)
Term
 Approval Voting
Definition
 Each voter submits a ballot that indicates which candidates he approves of. Winning is determined by the total number of approval votes.
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