Mixed-member proportional (MMP) representation is a mixed electoral
system in which voters get two votes: one to decide the representative
for their single-seat constituency, and one for a political party.
Seats in the legislature are filled firstly by the successful
constituency candidates, and secondly, by party candidates based on
the percentage of nationwide or region-wide votes that each party
received. The constituency representatives are elected using
first-past-the-post voting (FPTP) or another plurality/majoritarian
system. The nationwide or region-wide party representatives are, in
most jurisdictions, drawn from published party lists, similar to
party-list proportional representation. To gain a nationwide
representative, parties may be required to achieve a minimum number of
constituency candidates, a minimum percentage of the nationwide party
vote, or both.
MMP differs from parallel voting in that the nationwide seats are
allocated to political parties in a compensatory manner in order to
achieve proportional election results. Under MMP, two parties that
each receive 25% of the votes may both end up with 25% of the seats,
even if one party wins more constituencies than the other.
MMP was originally used to elect representatives to the German
Bundestag, and has been adopted by Bolivia,
Lesotho and New Zealand.
It was also used in
Romania during its 2008 and 2012 legislative
elections. In Germany, where it is used on the federal level and in
most states, MMP is known as personalized proportional representation
(German: personalisiertes Verhältniswahlrecht). In the United Kingdom
such systems used in Scotland, Wales, and the London Assembly are
referred to as additional member systems. In the Canadian
province of Quebec, where an MMP model was studied in 2007, it is
called the compensatory mixed-member voting system (système mixte
avec compensation or SMAC).
1.1 Calculation methods
1.2 Overhang seats
2 Governments with MMP
2.1 Current usage
2.2 Former usage
2.3 Proposals for use
2.3.3 Sri Lanka
3 Potential for tactical voting or collusion
3.1 Tactical voting
4 See also
6 Further reading
7 External links
Results of the 2017 German federal election. The image shows both the
seats directly won by constituency representatives and those gained
via party lists. For example, the FDP party (yellow) did not win a
single constituency; all its 80 MPs were elected on party lists.
In most models the voter casts two votes: one for a constituency
representative and one for a party. In the original variant used in
Germany, both votes were combined into one, so that voting for a
representative automatically meant also voting for the
representative's party. Most of
Germany changed to the two-vote
variant to make local members of parliament (MPs) more personally
accountable. Voters can vote for the local person they prefer for
local MP without regard for party affiliation, since the partisan
make-up of the legislature is determined only by the party vote. In
New Zealand election, 27.33% of voters split their vote
(voted for a local candidate of a different party than their party
vote) compared to 31.64% in 2014.
In each constituency, the representative is chosen using a single
winner method, typically first-past-the-post (that is, the candidate
with the most votes, by plurality, wins).
Most systems used closed party lists to elect the non-constituency MPs
(also called list MPs). In most jurisdictions, candidates may stand
for both a constituency and on a party list (referred to in New
Zealand as dual candidacy), but in Wales are restricted to contend
either for a constituency or for a party list, but not both. If a
candidate is on the party list, but wins a constituency seat, they do
not receive two seats; they are instead crossed off the party list and
replaced with the next candidate down.
Bavaria the second vote is not simply for the party but for one of
the candidates on the party's regional list:
Bavaria uses seven
regions for this purpose. A regional open-list method was also
recommended for the
United Kingdom by the Jenkins Commission (where it
is known as AMS) and for
Canada by the Law Commission of Canada. The
open-list method of MMP was also chosen in November 2016 by voters in
the Prince Edward Island electoral reform referendum, 2016.
Baden-Württemberg there are no lists; they use the "best
near-winner" method in a four-region model, where the regional members
are the local candidates of the under-represented party in that region
who received the most votes in their local constituency without being
elected in it.
At the regional or national level (i.e. above the constituency level)
several different calculation methods have been used, but the basic
characteristic of the MMP is that the total number of seats in the
assembly, including the single-member seats and not only the
party-list ones, are allocated to parties proportionally to the number
of votes the party received in the party portion of the ballot. This
can be done by the largest remainder method or a highest averages
method: either the
D'Hondt method or the Sainte-Laguë method.
Subtracted from each party's allocation is the number of constituency
seats that party won, so that the additional seats are compensatory
(top-up). If a party wins more FPTP seats than the proportional quota
received by the party-list vote, these surplus seats become overhang
seats to work towards restoring a full proportionality. In most German
states, but not federally until the federal election of 2013, "balance
seats" are added to compensate for the overhang seats and achieve
complete proportionality. In one election in Scotland, the highest
averages method resulted in a majority government for the Scottish
National Party with only 44% of the party vote. However, Scotland uses
Additional Member System which, like MMP is sometimes less
than perfectly proportional.
See also: Overhang seat
When a party wins more constituency seats than it would be entitled to
from its proportion of (party list) votes, overhang seats can occur.
Bundestag and the
New Zealand House of Representatives,
all these constituency members keep their seats. For example, in New
Zealand's 2008 General
Māori Party won 2.4% of the Party
Vote, which would entitle them to 3 seats in the House, but won 5
constituency seats, leaving an overhang of 2 seats, which resulted in
a 122-member house. If the party vote for the
Māori Party had been
more in proportion with the constituency seats won, there would have
been a normal 120-member house.
In most German states, and in the federal
Bundestag since 2013, the
other parties receive extra seats ("balance seats") to create full
proportionality. For example, the provincial parliament (Landtag) of
North Rhine Westphalia has, instead of the usual 50% compensatory
seats, only 29% unless more are needed to balance overhangs. If a
party wins more local seats than its proportion of the total vote
justifies, the size of the
Landtag increases so that the total outcome
is fully proportional to the votes, with other parties receiving
additional list seats to achieve proportionality.
As in numerous proportional systems, in order to be eligible for list
seats in many MMP models, a party must earn at least a certain
percentage of the total party vote, or no candidates will be elected
from the party list. Candidates having won a constituency will still
have won their seat. In
New Zealand the threshold is 5%, in Bolivia
Germany 5% for elections for federal parliament and most state
parliaments. A party can also be eligible for list seats if it wins at
least three constituency seats in Germany, or at least one in New
Zealand. Having a member with a 'safe' constituency seat is therefore
a tremendous asset to a minor party in New Zealand.
Governments with MMP
Ballot for electoral district 252, Würzburg, for the 2005 German
federal election. Constituency vote on left, party list vote on right.
MMP is currently in use in:
Bolivia adopted MMP in 1994.
Bundestag, the federal parliament (see
Electoral system of Germany)
most state parliaments. Exceptions are Baden-Württemberg, Bremen,
Hamburg and Saarland, but it is being introduced in Hamburg: see
Elections in Hamburg.
Lesotho adopted MMP in 2002.
New Zealand adopted the system for its unicameral House of
Representatives in 1994 following a long electoral reform process,
beginning with the
Royal Commission on the Electoral System
Royal Commission on the Electoral System in 1985
and ending with the 1993 referendum on the voting system. It was first
used in an election in 1996. The system's use was reviewed by
referendum in November 2011, with the majority (56.17%) voting to keep
Electoral system of New Zealand
United Kingdom – though the UK Parliament does not use MMP, two
constituent countries use MMP (referred to as the additional member
system) in their devolved parliaments:
Scotland – the devolved
Scottish Parliament uses MMP.
Wales – the devolved
National Assembly for Wales
National Assembly for Wales uses MMP.
Albania used MMP from 2001 to 2005 (after having used parallel voting
in the 1996 and 1997 elections).
Hungary used a variant of MMP, but with two rounds for the
constituency seats and an additional regional party list portion in
2010 and earlier. For the 2014 election and later the system was
changed so that the party list vote lost relative weight, and the
overall effect became less proportional.
Italy used MMP from 1994 to 2006.
Romania used MMP at the 2008 and 2012 legislative elections. For the
2016 elections, closed party-list proportional representation was used
See also: Elections in Romania
Venezuela MMP was previously used for elections, but the link between
list and constituency representatives was removed in 2009.
Proposals for use
In March 2004 the
Law Commission of Canada proposed a system of
MMP, with only 33% of MPs elected from regional open lists, for
the Canadian House of Commons but Parliament’s consideration of
the Report in 2004-5 was stopped after the 2006 election.
New Democratic Party
New Democratic Party of
Canada has been a longtime supporter of
A proposal to adopt MMP with closed province-wide lists for elections
Legislative Assembly of Prince Edward Island
Legislative Assembly of Prince Edward Island was defeated in a
referendum in 2005.
In 2007 the Citizens' Assembly on Electoral Reform in Ontario, Canada,
also recommended the use of MMP in future elections to the Legislative
Assembly of Ontario, with a ballot similar to New Zealand's, and with
the closed province-wide lists used in
New Zealand but with only 30%
compensatory members. A binding referendum on the proposal, held in
conjunction with the provincial election on 10 October 2007, saw it
In June 2016, the
Canadian House of Commons
Canadian House of Commons
Special Committee on
Electoral Reform was formed to examine potential changes to the voting
system with MMP being one of the options examined. The committee
presented its report to Parliament on 1 December of the same year. In
early 2017, the Government announced that it would accept only some of
the committee's recommendations, and would not pursue the issue of
electoral reform any further.
In a non-binding plebiscite between 27 October and 7 November, Prince
Edward Islanders voted for MMP over FPTP in the final round of
counting, 52%–43%; however, the provincial government, despite
having set no voter turnout threshold, subsequently claimed that the
36 percent turnout was insufficient to change the electoral
In 2015, Thailand's Constitutional Drafting Committee proposed use of
MMP for future national elections.
In September 2015, Sri Lankan Foreign Minister Mangala Samaraweera
announced they will change the country's system to MMP 
Potential for tactical voting or collusion
In systems with a threshold, people who prefer a larger party may
tactically vote for a minor party that is predicted to poll close to
or slightly below the threshold. Some voters may be afraid the minor
party will poll below the threshold, and that that would weaken the
larger political camp to which the minor party belongs. For example,
the German moderate-right Free Democratic Party (FDP) has often
received votes from voters who preferred the larger Christian
Democratic Union (CDU) party, because they feared that if the FDP
received less than 5% of the votes, the CDU would have no
parliamentary allies and would be unable to form a government on its
own. This tactical voting also ensures that fewer votes are wasted,
but at the cost of giving the FDP more seats than CDU voters would
ideally have preferred. This tactic is the same in any method of
Similarly, in New Zealand, some voters who preferred a large party
have voted for the minor party's local candidate to ensure it
qualifies for list seats on the back of winning a single electorate.
This notably occurred in the right-wing inner Auckland electorate of
Epsom in 2008 and 2011, where the National Party voters gave their
local vote to the ACT Party. In this case the tactic maintained some
proportionality by bypassing the 5% threshold, but is largely
disfavoured by the public due to it awarding smaller parties extra
list seats while parties with a higher party vote percentage that
don't win an electorate receive no seats; this occurred in 2008 when
ACT was awarded 5 seats on the back of one electorate seat and 3.7% of
the party vote, while
New Zealand First with no electorate seats and
4.1% of the party vote were awarded none. In 2011, some Epsom voters
voting for the left-wing Labour and Green parties tried to block the
tactic by giving their local vote to the National candidate; while it
was unsuccessful, it did reduce ACT's majority over National from
12,900 to 2,300. In August 2012, the initial report on a review of the
MMP system by the Electoral Commission recommended abolishing the one
electorate seat threshold, meaning a party winning an electorate seat
but not crossing the 5% threshold (which the same report recommends
lowering to 4%) is only awarded that electorate seat.
In other cases a party may be so certain of winning a large number of
constituency seats that it expects no extra seats in the proportional
top-up (list seats). Some voters may therefore seek to achieve double
representation by voting tactically for another party in the regional
vote, as a vote for their preferred party in the regional vote would
be wasted. This tactic is much less effective in MMP models with a
relatively large share of list seats (50% in most German states, and
42.5% in the
New Zealand House of Representatives) and/or ones which
add "balance seats", leading to less opportunities for overhangs and
maintaining full proportionality even when a party wins too many
This sort of strategy for a coalition of parties to capture a larger
share of list seats may be adopted formally as a strategy. By way of
example, in Albania's 2005 parliamentary election, the two main
parties did not expect to win any list seats, so they encouraged
voters to use their list votes for allied minor parties. This tactic
was used to such an extent that it totally distorted the working of
the model, to the point that the parties that won list seats were
almost always different from the parties that won constituency seats.
Indeed, only one constituency member was elected from parties that won
list seats. Rather than increasing the number of list seats or
Albania subsequently decided to change to a
In an abusive gambit similar to that used in Albania, major parties
feeling that they are unlikely to win a large number of list seats
because of their advantage at the constituency level might choose to
split their party in two, with one subdivision of the party contesting
the constituency seats, while the other contests the list seats
—assuming this is allowed by electoral law. The two linked parties
could then co-ordinate their campaign and work together within the
legislature, while remaining legally separate entities. The result of
this approach, if it is used by all parties, would be to transform MMP
into a de facto Mixed Member Majoritarian MMM or Parallel voting
mechanism. The election itself was condemned by the Organization for
Security and Co-operation in Europe which said it failed to comply
with international standards because of “serious irregularities,”
intimidation, vote-buying and “violence committed by extremists on
An example of how this could happen manifested itself in the 2007
Lesotho general election. In this case the two leading parties, the
Lesotho Congress for Democracy (LCD) and the All Basotho Convention
(ABC) used decoy lists, respectively named the National Independent
Party and the
Lesotho Workers' Party to avoid the compensatory
mechanisms of MMP. As a result, the LCD and its decoy were able to
take 69.1% of the seats with only 51.8% of the vote. ABC leader Tom
Thabane called the vote "free, but not fair." In the 2012 election,
the voting system was adjusted to link the local and list seats to
limit the decoy lists' effectiveness, resulting in an almost perfectly
proportionate election result for the competing parties.
Another interesting case is that of Venezuela, which also ended up
changing its system, in this case by formally adopting a parallel
voting system and legitimizing party efforts to game the MMP approach.
Venezuela introduced an MMP electoral system in 1993, but the tactic
of creating a decoy party was introduced only in 2000, by the
opposition governor of Yaracuy. The tactic was later adopted by
pro-Chavez parties at the national level in 2005. After the decoy list
tactic withstood a constitutional challenge,
formally reverted to a parallel voting system, which yields a lesser
degree of proportionality compared to MMP. On September 26, 2010,
Chavez' party, the United Socialist Party of Venezuela, took 57.4% of
parliamentary seats with only 48.2% of the vote under the new system
(ignoring the role of small allied parties). One can see to what
extent parallel voting had nonetheless helped to redress the balance
towards proportionality somewhat by noting that Chavez' party would
have taken an even larger share of assembly seats under a strict
single-winner approach (71 constituency seats out of 109, or 65%).
A final example is that of the Italian general election, 2001, in
which one of the two main coalitions (the House of Freedoms, which
opposed the scorporo system, (an alternate version of MMP), linked
many of their constituency candidates to a decoy list (liste civetta)
in the proportional parts, under the name Abolizione Scorporo. As a
defensive move, the other coalition, Olive Tree, felt obliged to do
the same, under the name Paese Nuovo. This meant that the constituency
seats won by each coalition would not reduce the number of list seats
available to them. In the case the
House of Freedoms list faction
Forza Italia, the tactic was so successful that it did not have enough
candidates in the proportional part to receive as many seats as it in
fact won, missing out on 12 seats.
Italy subsequently changed its
Alternative Vote Plus
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Venezuela Passes New Electoral Law". Retrieved 31
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Handbook of Electoral System Choice
6 min. video explaining how MMP (recommended by the Law Commission of
Canada) could work in
Canada – Presented by the nonpartisan Fair
Vote Canada's Dennis Pilon, Associate Professor, Political Science,
Part of the politics and election series
Single-winner voting system
Positional voting system
Single transferable vote
Highest averages method
Largest remainder method
Alternative vote Plus
Single non-transferable vote
Proportional approval voting
Sequential proportional approval voting
Satisfaction approval voting
Table of voting systems by country
Voting system criteria
Condorcet loser criterion
Independence of clones
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Majority loser criterion
Mutual majority criterion
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