Jana Behm Math 320 July 7 2010 overview Voting Systems and how they can effect outcomes Majority Rule Plurality Voting Electoral College Majority Rule Straight forward Excellent for choosing between 2 candidates ID: 755252
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Slide1
Math and politicsA look at how math affects elections
Jana
Behm
Math 320
July 7, 2010Slide2
overviewVoting Systems and how they can effect outcomes
*Majority Rule
*Plurality Voting
*Electoral CollegeSlide3
Majority Rule*Straight forward
*Excellent for choosing between 2 candidates
*Most votes wins
*No single vote counts more than any other
*Potential problem: TIES (usually broken in some pre-arranged way)
*Another potential problem: difficult in a multi-party systemSlide4
Plurality Voting*More than 2 alternatives in an election
*Simply count the number of 1
st
place votes
*Possible that no candidate has the majority of the votes castSlide5
The math of Majority and plurality voting
*Majority voting: simple majority
>Votes cast: 100 with 2 candidates– winner needs a simple majority which is (100/2) +1 or 51 votes to win the election.
*Plurality voting: simple math
>Votes cast: 100 with 3 candidates – winner simply needs the most votes, not necessarily a majority of the votes cast.
Slide6
The math of Majority and plurality voting
Example: 1992 US Presidential Election
Total Votes Clinton Bush Perot
104,425,014 44,909,326 39,103,882 19,741,657
43.01% 37.45% 18.91%
Therefore Clinton was the winner, but did not receive the majority of the votes cast
Source: http://iun.edu/~mathiho/mathpol/fall00/chapter11.htmSlide7
U.s. electoral college*Each state is given an electoral numbers which equals the number of US representatives + the 2 senators that they have
*How are the representatives divided?
*Is this fair?
*2009 estimates US population to be 307,006,550 peopleSlide8
U.S. electoral college continued
State Population % of US pop Electoral votes % of electoral votes
MT 974989 0.32% 3 0.56%
IA 3007856 0.98% 7 1.30%
IL 12910409 4.21% 21 3.90%
FL 18537659 6.04% 27 5.02%
NY 19541453 6.37% 31 5.76%
TX 24782302 8.07% 34 6.32%
CA 36961664 12.04% 55 10.22%
US Population = 307,006,550 Electoral votes possible: 538
Source for population numbers: http://quickfacts.census.gov/qfd/states/17000.htmlSlide9
Winning an election but losing the popular vote
2000 Presidential Election
Candidate Popular Vote % Electoral Vote %
George W. Bush 50,460,110 47.87% 271 50.4%
Albert Gore Jr. 51,003,926 48.38% 266 49.4%
Neither candidate had a simple majority as there were 6 candidates on the ballot.
Plurality voting is not in effect in the United States
President Bush won 2 large electoral states, but MANY of the smaller states that added up for the electoral win
Mr. Gore won largely populated states, but not enough of them for electoral victory.
Source: http://www.uselectionatlas.org/RESULTS/national.php?f=0&year=2000Slide10
2000 electoral mapSlide11
Electoral MathThere are 538 electoral votes possible
Candidates must get a simple majority
538/2 +1 = 270 votes
Therefore, they can have a simple majority of electoral votes without having a majority of votes cast in an election or even the most votes cast.Slide12
Let’s play with the mathhttp://
www.archives.gov/federal-register/electoral-college/calculator.html
http://www.realclearpolitics.com/epolls/maps/obama_vs_mccain/?
map=1Slide13
conclusionDoes math effect election outcomes?
Can one state change the entire course of an election with as little as 3 electoral votes?
How many configurations of states will give you the 270 needed to win? Are the big states mandatory, or do they just make
it easier?