1. VOTING
METHODS
JJ
Joey
Savan

2. VOTING METHODS
Borda
Approval
Pairwise Comparison
Plurality
Instant runoff

3. BORDA METHOD
 Single-winner election method
 Voters rank candidates in order of
preference
 Each candidate is given a certain number of
points corresponding to the position in
which he or she is ranked by each voter
 Once votes are counted, the candidate with
the most points wins
 Called consensus-based electoral system
because not chosen by majority

4. HISTORY OF BORDA METHOD
 Named for 18th-century French mathematician &
political scientist Jean-Charles de Borda
 Devised the system in 1770
 Used throughout the world by various private
organizations and competitions
 Used for:
 Election of two ethnic minority members of the
National Assembly of Slovenia
 To select presidential election candidates in Kiribati
 To elect members of the Parliament of Nauru

5. INSTANT RUNOFF VOTING
 Method of preferential voting
 Ranked choice voting
 Voters choose rank of candidates in order of preference
instead of just voting for one person
 Person with lowest number votes dropped and the people
vote again and again until there is only 1 person left
 Forces voters to vote more strategically
 Used to elect President of India and Ireland
 Used to elect leaders for the Labor Party in the United
Kingdom

6. INSTANT RUNOFF VOTING FLOWCHART

7. HISTORY OF INSTANT RUNOFF VOTING
 1850 – Thomas Hare invents the Single
Transferable Vote (STV) that is to elect several
minority winners representing the people who
elected them through ranked voting
 1870 - America W.R. Ware professor at MIT makes
changes to the STV system and develops the
Instant Runoff Voting system
 Goal of the IRV is to produce a single majority winner
 1893 – A modified version of Instant Runoff Voting
used in a governmental election in Queensland,
Australia
 Different because all candidates except the top two
were eliminated

8. APPROVAL METHOD
 Each voter can approve of as many options as he
or she wishes
 The winner is the candidate with the most votes
 Each candidate is treated as a separate question
 “Do you approve of this candidate”
 Don’t just vote for top choice
 Say if you would be okay with each candidate

9. APPROVAL VOTING EXAMPLE
 First period high school physical education class has decided to take a
vote to determine which activity they will take up next in PE. Their
choices are aerobics (A), badminton (B), football (F), or softball (S).
 The winning activity will be determined using Approval Voting.
 Suppose the following summarizes the responses of the classs
 12 students vote for Aerobics and Badminton
 5 students vote for Badminton, Football, and Softball
 10 students vote for Football and Badminton
 13 students vote for Softball and Badminton
 The activity with the most votes wins.

10. PAIRWISE COMPARISON
 Compare each possible match
 If there are four candidates, then you will compare:
 1 v 2
 1 v 3
 1 v 4
 2 v 3
 2 v 4
 3 v 4
 The candidate with the most “wins” is the winner

11. PAIRWISE COMPARISON EXAMPLE
 For instance, in a 4 candidate election, suppose
candidate A beats candidates B and D head-to-head,
candidate B beats candidate D and ties candidate C
head-to-head, candidate C beats candidate A and ties
candidate B head-to-head, and candidate D beats
candidate C head-to-head. Candidate A would get 2
points(1 each for beating B and D), candidate B would
get 1.5 points (1 point for beating D and half a point for
the tie with C), candidate C would get 1.5 points(1 point
for beating A and half a point for the tie with B),
and candidate D would get 1 point (for beating C). Since
candidate A has the highest point total,candidate A is the
winner by the Method of Pairwise Comparisons.

12. PLURALITY VOTING SYSTEM
 Single winner voting
system
 Used to elect executive
officers or to elect
members of a legislative
assembly
 Used in multi-member
constituencies in what is
referred to as an
exhaustive counting
system where one
member is elected at a
time and the process is
repeated until the number
of vacancies is filled.