|
Electoral
system
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Districts
|
Type
|
Description
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first-past-the-post
(FPTP)
|
single-member
|
plurality
|
The
candidate that obtains more votes than any other is
elected, even if that person only won a minority of
votes cast
|
|
two-round
system (TRS)
|
single-member
|
majority
|
A
runoff election is held between the two top vote-getters,
in order to ensure that the winner obtains a majority
of votes cast
|
|
alternative
vote (AV), or instant runoff
|
single-member
|
majority
|
Voters
indicate an order of preference among candidates. If
no candidate obtains a majority outright, the last-place
candidate is removed, and the associated second-choice
votes are added to the totals of the remaining candidates.
The process is repeated until a candidate secures a
majority.
|
|
block
vote (BV)
|
multiple-member
|
plurality
|
Voters
may cast as many votes as there are open seats. If there
are n seats to be filled, the top n vote-getters are
elected
|
|
single
non-transferable vote (SNTV)
|
multiple-member
|
semi-proportional
|
Voters
can only cast a single vote among candidates for n seats.
The top n vote-getters are elected.
|
|
single
transferable vote (STV), also known as preference or
choice voting
|
multiple-member
|
proportional
|
Voters
indicate an order of preference among candidates. Candidates
whose first-choice vote totals attain the Hare Quota—(votes
cast/n+1) + 1— are elected. The last-place candidate
is removed, and the associated second-choice votes are
added to the totals of the remaining candidates. The
process is repeated until all n seats are filled.
|
|
mixed
member proportional (MMP)
|
mixed
|
proportional
|
The
legislature consists of a block of seats that are elected
by plurality or majority from single-member districts,
and another block of seats that are elected in multi-member
districts under a proportional system. The proportional
seats are awarded in such a way as to compensate for
disproportional effects in the single-member district
outcomes.
|
|
parallel
|
mixed
|
semi-proportional
|
The
legislature consists of a block of seats that are elected
by plurality or majority from single-member districts,
and another block of seats that are elected in multi-member
districts under a proportional system. The proportional
seats are awarded independently of the outcomes in single-member
districts.
|
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party
list
|
multiple-member
|
proportional
|
Voters
choose from among party lists, and seats are awarded
in proportion to the vote received by each party. Candidates
are seated in the order listed.
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TYPES
OF ELECTORAL SYSTEMS