PLURALITY/MAJORITY SYSTEMS
This plurality/majority family of voting systems is
undoubtedly the one most familiar to Americans. They are the winner-take-all
systems we most often use to elect officials to our local, state, and federal
legislatures. These systems all require the winning candidate to garner either a
plurality or a majority of the votes. We inherited this approach to voting from
the British, and plurality-majority systems are used today primarily in Great
Britain and its former colonies, including the United States, Canada, Australia,
and India. The main purpose of these systems is to represent the majority or
plurality of voters in a district, and (with the exception of at-large voting)
to ensure representation of local geographical areas.
Four types of plurality-majority voting systems are described
below. The first two are the commonly-used plurality systems: single-member district
and at-large voting. Less common are the two majority systems that use
runoffs: the two-round system, and instant runoff voting .
Single-member district plurality voting.
At-large voting.
Two-round runoff voting.
Instant runoff voting.
Single-Member District Plurality Voting
Single-member district plurality voting (SMDP) is the system most commonly
used for legislative elections in the United States. It is the one most people
think of when they think of the word "voting." In Great Britain and
Canada, this system is often called "first-past-the-post."
How It Works. In this system, all the candidates appear on the ballot and
the voters indicate their choice of one of them--by marking an X, pulling a
voting lever, etc. (See example below.) All the votes are then counted and the
winner is the one with the most votes. Winners need not collect a majority of
the votes, only more votes than their opponents do--a plurality of the votes. So
if candidate A receives 40% of the vote, candidate B receives 35%, and candidate
C gets 25% -- candidate A wins the seat.
Single-Member District Plurality Ballot
Political Attributes. SMDP is good at ensuring that
the plurality of voters are represented and that all local geographical areas
have a voice in the legislature. It also tends to reinforce the two-party
system, and to produce stable single-party majorities in legislatures. It
does this by making it difficult for third parties to elect their candidates.
This also serves as a check on small extremist parties. On the other hand, this
voting system also tends to misrepresent
parties, produce manufactured majorities, encourage gerrymandering, discourage
voter turnout, create high levels of wasted votes, and deny fair representation
to third parties, racial minorities and women.
This system is unique among plurality-majority systems in that it uses
multi-member districts instead of single-member districts. For that reason
political scientists often refer to it as "multi-member district
plurality" voting. Internationally it is often called "block
voting." Many representatives to state legislatures and even the U.
S. Congress were at one time elected in multi-member districts--often small two
or three seat districts. Ten states still use some of these districts for state
legislative elections. Today, however, at-large voting is used primarily in
local elections, primarily municipal elections. Typically an entire town or city
is considered to be one large district, and all candidates for office run
together against each other.
How It Works. In at-large voting, all the candidates for office run in
one large multi-member district -- usually the entire city. Voters have
the same number of votes as the number of seats to be filled. The candidates
with the highest numbers of votes (a plurality) win. Below is a ballot that
would be used in a city election in which the members of a five-person city
council would be chosen. All candidates for the five seats are on the ballot and
voters cast five votes for the candidates they prefer. The following table
illustrates how the votes might be distributed and the winners chosen.
At-Large Ballot
At-Large Voting Results
There are several variations of at-large voting. In one of them that is used
in Seattle and several other cities, the at-large seats are numbered and
specific candidates vie for these individual seats. So candidates A and B would
vie for seat one, candidates C and D for seat two, and so on. All the voters in
the city cast one vote for their preferred candidates in each of these races,
and the candidate with the plurality wins. In another variation, some cities use
the numbered seats, but also have a residency requirement. Candidates for a
particular seat must live in a certain area or district of the city. This
ensures that all neighborhoods have some representation. Again all the voters in
the city are able to vote for each of the seats.
Political Attributes. At-large voting gives good representation
to the largest political group or party. It is also designed to ensure that city councilors represented the
interests of the city as a whole, not the special interests of particular
neighborhood districts. Like SMDP, it also encourages a two-party system and
single-party legislative majorities. In addition, since there are no districts, this voting systems
eliminates the possibility of gerrymandering. However, because this is a
winner-take-all system, at-large voting shares most of the same problems as
single-member district plurality voting, including the
misrepresentation of parties, manufactured majorities, low voter turnout, high
levels of wasted votes, and denial of fair representation to third parties, racial
minorities and women. And it may make some of these problems worse. In
particular, this system tends to be the worst at representing racial and
political minorities. It allows a majority of the voters to win all the seats on
the city council, thus shutting out these minorities from representation. (Note
that in the election described above, the Republican voters are in the majority
and so are able to elect all the city councilors.) Finally, at-large
voting, in its most common form, fails to ensure that all neighborhoods in the city are represented.
The two-round system (TRS) is a majority voting system. Majority systems are
currently used less commonly than plurality systems. They require
candidates in single-member district elections to garner a majority of the votes
to win legislative office. TRS requires a runoff election between the two top
candidates if no candidate wins a majority of the votes in the general election.
This system is designed to solve one of the obvious problems of plurality
voting: the possibility of electing a candidate that was supported only by a
minority of the electorate in the district.
TRS is used rarely worldwide. Only two countries in Western Europe
use TRS for legislative elections, France and Monaco. Several developing
countries that came under French influence also use this system,
including Mali,
Togo, Chad, Gabon, and Haiti. In the United States, TRS is used in a
number of jurisdictions,
mostly on the local level and mostly in the South. Runoffs first came
into use
here at the beginning of the twentieth century when parties began to
have
primaries. These primaries often attracted more than two candidates and
the
resulting winner would sometimes garner much less than a majority of the
vote.
Today, runoffs are also used in some U.S. cities that have non-partisan
elections, again primarily because such contests are more likely to draw
more
than two candidates.
How It Works. In order to ensure that the winning candidate receives a
majority of the vote, this system uses two rounds of voting with polling taking
place on two separate days. Ballots are identical to those used in plurality
voting (see above), and voters mark them in the same way. In the first round,
all candidates are listed on the ballot and voters indicate their preference of
one of them. All these votes are then added up and if a candidate receives a
majority of the vote (50% + 1 vote), that candidate is declared elected. If no
one receives a majority, the field is cut down to the top two candidates who
received the highest number of votes, and a runoff election is held. The second
election is typically held several weeks after the first. The winner is the
candidate who gets the most votes, which is inevitably a majority, since there
are only two candidates running.
Political Attributes. The two-round runoff system is only a slight modification of the
single-member district plurality system, and it is really only designed to
address one of its problems -- the possibility of a plurality winner -- which it
does eliminate. It also does well in encouraging a two-party system and
single-party legislative majorities. However, it is still
a winner-take-all voting system and so it shares all the basic problems of this
approach to voting, including the misrepresentation of parties, manufactured
majorities, gerrymandering, high levels of wasted votes, and
denial of fair representation to third parties, racial minorities and women. In
addition, it brings with it two more problems: the added expense of a second
election, and the lower voter turnout that usually plagues those second
elections.
Instant runoff voting is also known as "IRV," and "majority
preferential voting." In Australia, where this system is used to elect
their lower house of parliament, it is called the "alternative vote."
Like two-round voting, this majority system a minor variation of single-member
district plurality voting that was developed to ensure that the winning
candidate enjoys the support of the majority of the voters in the district. It
was also thought to be an improvement over the two-round system because it does
not require a separate election--it provides an "instant" runoff.
How It Works. In IRV voting, like plurality voting, all candidates are
listed on the ballot. But instead of voting for only one candidate, voters rank
the candidates in the order of their preference. This ranking process is
illustrated in ballot below. It is an AccuVote ballot, which allows ballots to
be scanned and tabulated by computer. It is similar to marking answers on the
standardized tests used in schools. On this ballot, voters fill in numbered
boxes to indicate their ranking of the candidates. The mark a "1" for
their most preferred candidate, a "2" for their second preference, and
so on.
Instant Runoff Ballot
The counting of the ballots is also different from plurality voting. First,
all the number one preferences of the voters are counted. If a candidate
receives over 50% of the first choice votes, he or she is declared elected. If
no candidate receives a majority, then the candidate with the fewest votes is
eliminated. The ballots of supporters of this defeated candidate are then
transferred to whichever of the remaining candidates they marked as their number
two choice. (It is as if you told the supporters of the last place candidate,
"Your candidate cannot possibly win, so which of the remaining candidates
would you like your vote to go to?) After this transfer, the votes are then
recounted to see if any candidate now receives a majority of the vote. The
process of eliminating the lowest candidate and transferring their votes
continues until one candidate receives a majority of the continuing votes and
wins the election.
This transfer process is illustrated in the table below. In this hypothetical
election, there are 100,000 votes cast and no candidate receives over 50% of the vote in the first round. So the
lowest candidate--Royce--is eliminated and his ballots are transferred to their
second choices. 1,000 of Royce’s supporters gave Chou as their second choice,
and 6,000 indicated Kleinberg as their second choice. The new totals show that
no one yet has a majority, so Chou is eliminated. 4,000 of Chou's votes are
transferred to Kleinberg and 5,000 are given to Rosen. (If some of Chou's
ballots had listed Royce as the second choice, they would have been transferred
to their third choice, since Royce had been eliminated.) After this latest
transfer is it clear that Kleinberg now has over 50% of the vote and she is
declared the winner. As this example illustrates, this system essentially
operates as a series of runoff elections, with progressively fewer candidates
each time, until one candidate gets a majority of the vote.
Vote Counting in Instant Runoff Voting
Political Attributes. IRV has the advantage
of the two-round system
-- ensuring a majority winner -- while avoiding its major disadvantages:
the
added expense and lower voter turnout of a second election. However,
being in the plurality-majority family of voting systems, IRV shares
most of the political disadvantages of this winner-take-all approach,
including the misrepresentation of parties, manufactured majorities,
gerrymandering, low voter turnout, high levels of wasted votes, and
denial of
fair representation to third parties, racial minorities and women.
https://www.mtholyoke.edu/acad/polit/damy/BeginnningReading/plurality.htm
