day 2 & 3 Plurality Borda and Runoff
A B C D B C D B C A B C D D A A
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1) How many voters are in this election? 2) Which option received the most 1st preferences?
1 day 2 & 3 Plurality Borda and Runoff
Methods for Determining an Election
• Two methods for first place only • Plurality winner – Who has the most votes? • Majority winner – The winner must have more than half of the votes.
2 day 2 & 3 Plurality Borda and Runoff
Borda Method
• Named after Jean-Charles de Borda • Naval captain • Created a book of logarithms • Crater on moon named after him
The Borda Method
• 1st place gets n points times the number of votes ranking that object or person first, 2nd place is n – 1, etc. • Sum the values together. • Whoever has the largest sum wins.
3 day 2 & 3 Plurality Borda and Runoff
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4 day 2 & 3 Plurality Borda and Runoff
Benefits and Downfalls • Benefits • Takes into account candidate that welcomes extreme views • Elects someone more feel “ok” with
• Downfalls • May elect someone middle of the road • Allows for ties
5 day 2 & 3 Plurality Borda and Runoff
6 day 2 & 3 Plurality Borda and Runoff
7 day 2 & 3 Plurality Borda and Runoff
A B C D B C D B C A B C D D A A
12 8 10 6
1) Find the winner using Plurality. Is it a Majority? 2) Find the winner using Borda Count Method. 3) Find the winner using Instant Runoff.
Runoff Methods
• What happens if you require a majority winner but no one wins majority? • This can cause many problems. • How are states dealing with this? • Instant Runoff (Plurality with runoff)
8 day 2 & 3 Plurality Borda and Runoff Instant Runoff Methods • Choose the two candidates that have the most first-place votes. • Eliminate other choices. • See who has the higher rankings now. Is there a majority?
9 day 2 & 3 Plurality Borda and Runoff Instant Runoff • Pros • If you have preferential voting to begin with, it would be easy to decide a vote when there is no majority winner. • Cheaper than holding another election. • Cons • Plurality winner can end up losing.
Sequential Runoff Method (Plurality with elimination)
• Eliminates one choice at a time. • Eliminate the candidate with the least first place votes. • Those first place votes get reassigned to the person below. • Continue until you have a winner.
10 day 2 & 3 Plurality Borda and Runoff Examples of Sequential Runoff Method
Sequential Runoff
• Pros: • Gets rid of the “worst” and gives the votes to others.
• Cons: • You can end up with a “tie” and not be able to finish the method.
11 day 2 & 3 Plurality Borda and Runoff Condorcet Method
• Developed by Marquis de Condorcet
• Condorcet Method • The candidate that can obtain a majority over all other individual candidates. • See how many times A beats B (is it a majority?) and A beats C, etc. • If it is a majority every time, then that candidate is the winner.
• Pros • This person “truly” beats everyone else • Cons • Condorcet Paradox – No winner is found. Multiple candidates have majority over others.
12 day 2 & 3 Plurality Borda and Runoff More Examples with Condorcet
Practice – Complete with group and turn in!
• Which type of food is the plurality winner? • Majority? • Borda Count? • Instant Runoff? • Sequential Runoff? • Condorcet?
13 day 2 & 3 Plurality Borda and Runoff
14 day 2 & 3 Plurality Borda and Runoff
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