Part of the Politics series |
Electoral systems |
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Politicsportal |
A mixed electoral system or mixed-member electoral system combines methods of majoritarian and proportional representation (PR). [1] [2] [3] The majoritarian component is usually first-past-the-post voting (FPTP/SMP), [4] whereas the proportional component is most often based on party-list PR. The results of the combination may be mixed-member proportional (MMP), where the overall results of the elections are proportional, [2] or mixed-member majoritarian, in which case the overall results are semi-proportional, retaining disproportionalities from the majoritarian component.
Mixed-member systems also often combine local representation [5] (most often single-member constituencies) with regional or national (multi-member constituencies) representation, having multiple tiers. [6] This also means voters often elect different types of representatives who might have different types constituencies. Some representatives may be elected by personal elections where voters vote for candidates, and some by list elections where voter vote primarily for electoral lists of parties.
In most mixed systems, every voter can influence both the district-based and PR aspects of an election, [7] such as under parallel voting; in others, the voter casts just one vote (mixed single vote), which is used to contribute to both a personal (usually district) election and to the filling of seats through list system. [8] Most mixed systems have all the voters contributing to the election of both groups of members.
A major distinction is often made between mixed compensatory systems and mixed non-compensatory systems. [8] In both types of systems, one set of seats is allocated using a plurality or majoritarian method, usually First past the post. The remaining seats are allocated to political parties partially or wholly based on a proportional allocation method such as highest averages or largest remainder. The difference is whether or not the results of the district elections are considered when allocating the PR seats.
In mixed non-compensatory systems, such as parallel voting, [4] the proportional allocation is performed independently of the district election component.
In mixed compensatory systems, the allocation of the top-up seats is done in such a way as to compensate as much as possible for dis-proportionality produced by the district elections. MMP generally produces proportional election outcomes, meaning that a political party that wins n percent of the vote will receive roughly n percent of the seats.
The following hypothetical example based on the one by Massicotte [4] illustrates how "top-up" PR seats are typically allocated in a compensatory system and in a non-compensatory system. The example assumes a 200-seat legislative assembly where 100 seats are filled using FPTP and the other 100 seats are awarded to parties using a form of PR. The table below gives the popular vote and FPTP results. The number of PR seats allocated to each party depends on whether the system is compensatory or non-compensatory.
Party | Popular vote | FPTP seats | PR seats | Total seats (FPTP + PR) | FPTP seats | |
---|---|---|---|---|---|---|
Party A | 44% | 64 | ? | ? | ||
Party B | 40% | 33 | ? | ? | ||
Party C | 10% | 0 | ? | ? | ||
Party D | 6% | 3 | ? | ? | ||
TOTAL | 100% | 100 | 100 | 200 |
In non compensatory system, each party wins its proportional share of the 100 PR seats. Under such a system, the total number of seats (FPTP + PR) received by each party would not be proportional to its share of the popular vote. Party A receives just slightly less of the popular vote than Party B, but receives significantly more seats. In addition to its success in the district contests, Party A receives almost as many of the PR seats as Party B.
If the PR seats are allocated in a compensatory system, the total number of seats awarded to each party is proportional to the party's share of the popular vote. Party B wins 33 of the district seats and its proportional share of the 200 seats being filled is 80 seats (40 percent of the total 200 seats) (the same as its share of the popular vote) so it is awarded 47 of the PR seats.
In practice, compensatory seat allocation is complicated by the possibility that one or more parties wins so many of the district seats ("overhang") that the available number of PR seats is insufficient to produce a fully proportional outcome. [9] Some mixed compensatory systems have rules that address these situations by adding additional PR seats to achieve overall PR. These seats are used only until the next election, unless needed again at that time. [4]
The two common ways compensation occurs are seat linkage compensation (or top-up) and vote linkage compensation (or vote transfer). [9] Like a non-compensatory mixed system, a compensatory mixed system may be based on the mixed single vote (voters vote for a local candidate and that vote is used to set the party share of the popular vote for the party that the candidate belongs to) or it may be based on voters casting two separate votes. [10]
Compensatory mixed systems | ||
---|---|---|
single vote systems | dual vote systems | |
Seat linkage | mixed single vote, top-up versions (MSV)
| mixed-member proportional representation (MMP) |
additional member system (AMS) | ||
alternative vote plus (AV+) | ||
Hybrids: e.g. parallel voting+AMS (South Korea) | ||
Vote linkage | positive vote transfer (PVT/MSV)
| Hybrids:
|
Others systems: | ||
dual-member proportional (DMP) | mixed ballot transferable vote (MBTV) | |
Non-compensatory mixed systems | ||
single vote systems | dual vote systems | |
No linkage | - | parallel voting |
Vote linkage | mixed single vote, superposition
| - |
Seat linkage | List seats proportional to FPTP seats | - |
Apart from the compensatory/non-compensatory typology, a more detailed classification is possible based on how component systems relate to each other, according to academic literature. Below is a table of different categories of mixed electoral systems based on the five main types identified by Massicotte & Blais. [7] According to their terminology, methods of compensation are referred to as compensation is referred to as correction, while another type of dependent combination exists, called the conditional relation between sub-systems. Meanwhile, independent combinations mixed systems might have both local and national/regional tiers (called superposition), but some have only one at-large (national) tier, like the majority bonus system (fusion) or only a single tier for local/regional representation (called coexistence).
There are also supermixed systems, like rural-urban proportional (RUP), which is a hybrid mixed system that uses two tiers: the lower tier uses a proportional system, like list-PR or STV, in urban regions, and the upper tier uses MMP (itself a mixed system) either in rural regions alone or in all regions. [4] Another supermixed system is scorporo, which is a hybrid of parallel voting and the mixed single vote). [7]
Combination | Type | Attributes | System | Example(s) for use |
---|---|---|---|---|
Independent combination | Fusion | Two formulas are used within each district (or one district for the whole electorate) | Majority bonus (MBS) | |
Coexistence (hybrid) | Different districts use different systems in one tier | e.g. FPTP/SMP in single-member districts, list-PR in multi-member districts | Democratic Republic of the Congo, Panama | |
Superposition | Different tiers use different systems | Parallel voting (e.g. FPTP/SMP locally, list-PR nationally) | Lithuania, Russia | |
Single vote mixed-member majoritarian (e.g. FPTP/SMP locally, list-PR nationally) | Italy, Pakistan | |||
Dependent combination | Correction (compensation) | One formula uses the results of other to compensate | Mixed-member proportional representation (MMP) | Germany, New Zealand |
Additional member system (AMS) - the semi-proportional version of MMP | Scotland, Wales | |||
Compensatory versions of mixed single vote, like positive vote transfer systems (PVT) or single vote MMP | Lesotho, Bolivia | |||
Majority jackpot system | Armenia, San Marino | |||
Conditional | Outcome of one formula determines the other formula | e.g. conditional party block voting: party that receives more than 50%, gets all seats otherwise winner gets 50% of seats and rest is distributed proportionally | ||
Combination of combinations | Supermixed | Superposition + correction | Scorporo / negative vote transfer (NVT), Parallel voting + PVT, Parallel voting + AMS | Hungary, South Korea |
Superposition + Fusion | Majority bonus (MBS) | Greece (formerly) | ||
Coexistence + conditional | e.g. FPTP/SMP in single-member districts, conditional party block voting in multi-member districts | Cameroon, Chad | ||
Coexistence + correction | Rural-urban proportional representation (RUP) | Denmark (formerly), Iceland (formerly) | ||
Fusion + correction | Dual-member proportional representation (DMP) | - |
In a hybrid system, different electoral formulas are used in different contexts. These may be seen in coexistence, when different methods are used in different regions of a country, such as when FPTP is used in single-member districts and list-PR in multi-member districts, but every voter is a member of only one district (one tier). Some hybrid systems are generally not referred to as mixed systems, such as when as FPTP districts are the exception (e.g. overseas constituency) and list-PR is the rule, the overall system is usually considered proportional. Similarly, when FPTP is in single-member districts and used block voting (or party block voting) is used in multi-member districts, the system is referred to as a majoritarian one, as all components are majoritarian. Most mixed systems are not referred to as hybrid systems
Another distinction of mixed electoral systems is between mixed-member proportional representation (MMP) and mixed-member majoritarian representation (MMM).
Parallel voting is a mixed non-compensatory system with two tiers of representatives: a tier of single-member district representatives elected by a plurality/majoritarian method such as FPTP/SMP, and a tier of regional or at-large representatives elected by a separate proportional method such as party list PR. It is used for the first chamber (lower house) in many countries including Japan and Russia.
This type of parallel voting provides semi-proportional results, but is often referred to as mixed-member majoritarian representation, as the lack of compensation means each party can keep all the overhang seats it might win on the majoritarian side of the electoral system.
Like parallel voting, MMP and AMS also have a tier of district representatives typically elected by FPTP, and a tier of regional or at-large representatives elected by PR. Unlike parallel voting, MMP and AMS are mixed compensatory systems, meaning that the PR seats are allocated in a manner that corrects disproportionality caused by the district tier. MMP corrects disproportionalities by adding as many leveling seats as needed, this system is used by Germany and New Zealand.
The type of MMP which does not always yield proportional results, but sometimes only "mixed semi-proportional representation" is called an additional member system. If the fixed number of compensatory seats are enough to compensate the results of the majoritarian FPTP/SMP side of the election, AMS is equivalent to MMP, but if not, AMS does not compensate for remaining overhang seats. In Bolivia and Lesotho, where single vote versions of AMS are used with a relatively large number of compensatory seats, results are usually proportional. AMS models used in parts of the UK (Scotland and Wales), with small regions with a fixed number of seats tend to produce only moderately proportional election outcomes.
Electoral systems with a majority bonus have been referred to as "unconventional mixed systems". [11] Employed by Armenia, Greece, and San Marino, as well as Italy from 2006 to 2013, [12] majority bonuses help the most popular party or alliance win a majority of the seats with a minority of the votes, similar in principle to plurality/majoritarian systems. However, PR is used to distribute seats among the opposition parties, and possibly within the governing alliance.
Scorporo is a two-tier mixed system similar to MMP in that voters have two votes (one for a local candidate on the lower tier, and one for a party list on the upper tier), except that disproportionality caused by the single-member district tier is partially addressed through a vote transfer mechanism. [13] Votes that are crucial to the election of district-winning candidates are excluded from the PR seat allocation, for this reason the method used by scorporo is referred to as a negative vote transfer system. [14] The system was used in Italy from 1993 to 2005, and a modified version is currently used in Hungary. [15]
MBTV is a mixed compensatory type of systems similar to MSV, except voters can vote separately for a local candidate and as a transfer vote on the compensatory tier. [16] It is different from MMP/AMS and AV+ in that there is a vote linkage (instead of seat linkage) between the tiers. The two parts of the dual ballot are tied in a way that only those lists votes get counted, which are on ballots that would be transfer votes in an equivalent positive vote transfer MSV system.
AV+ is a mixed compensatory system similar to the additional member system, with the notable difference that the district seats are awarded using the alternative vote. The system was proposed by the Jenkins Commission as a possible alternative to FPTP for elections to the Parliament of the United Kingdom.
DMP is a mixed compensatory system similar to MMP, except that the plurality and PR seats are paired and dedicated to dual-member (two seat) districts. Proposed as an alternative to FPTP for Canadian elections, DMP appeared as an option on a 2016 plebiscite in Prince Edward Island and a 2018 referendum in British Columbia.
Most mixed systems allow voters to cast separate votes for different formulas of the electoral system, including:
MSV is a type of mixed systems using only a single vote that serves both as a vote for a local candidate and as a party list vote, split ticket voting is not possible. The system was used in Germany in a mixed proportional system, [10] and is currently used in Hungary as a semi-proportional system as well as Italy in a non-compensatory system. Other mixed systems using a single vote include majority bonus/jackpot systems and DMP.
Other systems that are usually considered mixed, which use a single vote are:
The RUP systems formerly used in Denmark and Iceland used a single vote, applicable both for the lower-tier constituencies - FPTP in the rural single-member constituencies, and list PR in the urban multi-member constituencies - and for the upper-tier national leveling seats (and in Denmark, also for the middle-tier regional leveling seats in rural areas). The implementation of RUP proposed in Canada foresees urban multi-member districts that use a single transferable vote, alongside single-member rural districts that are grouped in large multi-member regions; the rural districts and their corresponding regions.
A simultaneous vote is a single vote that used in more than one elections held at once, which means it is not a typically regarded as a mixed system.[ citation needed ]
The table below lists the countries that use a mixed electoral system for the first chamber of the legislature. Countries with coexistence-based hybrid systems have been excluded from the table, as have countries that mix two plurality/majoritarian systems. (See also the complete list of electoral systems by country.)
Country | Body | Latest election (year) | Type of mixed system | Seats per constituency | Mixed system | Component electoral systems | Total seats | Number of votes | Typical results | Notes |
---|---|---|---|---|---|---|---|---|---|---|
Andorra | General Council | 2023 | Non-compensatory | 2 (local districts), 14 (nationwide constituency) | Parallel voting (superposition) | Party block voting (PBV) and party-list PR | 28 | 2 | semi-proportional | The parish lists and the national list are independent of one another: the same person cannot appear on both the national list and on a parish list, and voters cast two separate ballots (there is no requirement to vote for the same party for both lists). [17] |
Argentina | Legislature of Córdoba Province | 2019 | Non-compensatory | 1 (local districts), 44 (nationwide constituency) | Parallel voting (superposition) | 70 | 2 | semi-proportional | ||
Legislature of Río Negro Province | Non-compensatory | |||||||||
Legislature of San Juan Province | Non-compensatory | |||||||||
Legislature of Santa Cruz Province | Non-compensatory | |||||||||
Armenia | Partially compensatory | Majority jackpot system | Party-list PR + party block voting (PBV) | |||||||
Bolivia | Chamber of Deputies | 2020 | Compensatory | 1 (local districts), ? (regional constituencies), 7 (indigenous seats elected by the usos y costumbres ) | Additional member system (AMS) - MMP without levelling seats | First-past-the-post (FPTP/SMP) + Party-list PR | 1 (mixed single vote) | proportional | Ballots use a double simultaneous vote with the presidential election [18] | |
Djibouti | National Assembly | 2018 | 3-28 | 65 | 80% of seats (rounded to the nearest integer) in each constituency are awarded to the party receiving the most votes (party block voting), remaining seats are allocated proportionally to other parties receiving over 10% (closed list, D'Hondt method) | |||||
Georgia | Parliament | 2020 | Non-compensatory | Parallel voting (superposition) | 150 | semi-proportional | ||||
Germany | Bundestag (lower house of the federal parliament) | 2021 | Compensatory | 1 (local districts), varies (regional constituencies), | Mixed-member proportional representation (MMP) - with levelling seats | Party-list PR + First-past-the-post (FPTP/SMP) | 598 + leveling seats | 2 | proportional | Referred to as personalized proportional representation, [19] in 1949 as a result of inter-party bargaining. [20] Originally used single vote version, switched to two vote version before the 1953 election. |
State parliaments, except | varies by state | Compensatory | varies by state | Mixed-member proportional representation (MMP) - with levelling seats | Party-list PR + First-past-the-post (FPTP/SMP) | varies by state | varies by state | Bavaria uniquely uses an open-list system for its party-list seats. Baden-Württemberg uses MMP without lists. | ||
Greece | Hellenic Parliament | 2019 | Non-compensatory | Majority bonus | semi-proportional | |||||
Guinea | National Assembly | 2020 | Non-compensatory | 1 (local districts), 76 (national constituency) | parallel voting (superposition) | Party-list PR (Hare quota) + First-past-the-post (FPTP/SMP) | 114 | semi-proportional | ||
Hungary | National Assembly (Országgyűlés) | 2018 | Partially compensatory | 1 (local districts), 93 (national constituency) | Supermixed: parallel voting (superposition) and positive vote transfer (correction) | First-past-the-post (FPTP/SMP) + national list-PR | 199 | 2 | semi-proportional | |
Italy | Chamber of Deputies | 2022 | Non-compensatory | 1 (147 single-member districts) 245 (national constituency, seats redistributed into 49 multi-member districts) 8 (Italians abroad constituency) [21] | Superposition | List PR + First-past-the-post (FPTP/SMP) | 400 | 1 (mixed single vote) | semi-proportional | mixed single vote |
Senate | 2022 | Non-compensatory | 1 (74 single-member districts) varies, cannot be less than 2 (20 regional constituencies, seats redistributed into 26 multi-member districts) 4 (Italians abroad constituency) [21] | Superposition | List PR + First-past-the-post (FPTP/SMP) | 200 | 1 (mixed single vote) | semi-proportional | mixed single vote | |
Japan | House of Representatives | Non-compensatory | Parallel voting (superposition) | First-past-the-post (FPTP/SMP) and List PR | 289 | 2 | ||||
House of Councillors | Non-compensatory | Parallel voting (superposition) | SNTV and List PR | 2 | ||||||
Republic of Korea (South Korea) | National Assembly | 2020 | Partially compensatory | 1 (local districts), 17 supplementary seats (parallel voting), 30 additional seats (AMS), | Supermixed parallel voting (superposition) and additional member system (correction) | Party-list PR + First-past-the-post (FPTP/SMP) | 2 | semi-proportional | ||
Kyrgyzstan | Supreme Council | 2021 | Non-compensatory | 1 (local districts), 54 (nationwide constituency) | Parallel voting (superposition) | Party-list PR + First-past-the-post (FPTP/SMP) | 2 | semi-proportional | ||
Lesotho | Compensatory | Additional member system (AMS) | 1 (mixed single vote) | proportional | ||||||
Lithuania | Seimas | Non-compensatory | Parallel voting (superposition) | TRS and List PR | 71 | semi-proportional | ||||
Mauritania | ||||||||||
Mexico | Chamber of Deputies | 2021 | Partially compensatory | 1 (local districts), 40 (multi-member districts) | Supermixed parallel voting (superposition) and additional member system (correction) | First-past-the-post (FPTP/SMP) + Party-list PR (Largest remainder:Hare quota) | 2 | semi-proportional | Since 1996, a party cannot get more seats overall than 8% above its result nationally (i.e., to win 50% of the legislative seats, a party must win at least 42% of the vote nationwide). There are three exceptions on this rule: first, a party can only lose PR-seats due to this rule (and no plurality-seats); second, a party can never get more than 300 seats overall (even if it has more than 52% of the vote nationally); and third, a party can exceed this 8% rule if it wins the seats in the single-member districts. | |
Chamber of Senators | 2018 | Non-compensatory | 3 (local districts), 32 (multi-member districts) | Superposition | Limited (party) block voting locally (2 seats from each constituency to largest party, 1 to the second largest party) + Party-list PR nationwide | 1 (mixed single vote) | semi-proportional | |||
Monaco | ||||||||||
Mongolia | ||||||||||
Morocco | ||||||||||
Nepal | ||||||||||
New Zealand | House of Representatives | Compensatory | mixed member proportional (MMP) | 2 | ||||||
Pakistan | National Assembly | Non-compensatory | Superposition,seat linkage non compensatory | First-past-the-post (FPTP/SMP) for 272 seats + 70 members appointed by parties proportional with seats already won | 1 | |||||
Philippines | House of Representatives | 2019 | Non-compensatory | Parallel voting (superposition) | ||||||
Russian Federation | State Duma | 2021 | Non-compensatory | Parallel voting (superposition) | ||||||
San Marino | Grand and General Council | 2019 | Non-compensatory | Majority bonus | semi-proportional | |||||
Senegal | National Assembly | 2017 | Non-compensatory | |||||||
Seychelles | National Assembly | 2020 | Non-compensatory | |||||||
South Africa | Municipal elections including: | 2021 | Compensatory | 1 | MMP with ca. 50% FPTP and 50% AMS | Varies by municipality | Two ballots - one with FPTP candidates (Ward) and the other with just party names (PR). Compensatory seats are based on the sum of both ballots, effectively allocated using the D'Hondt method. | |||
Sri Lanka | ||||||||||
Taiwan(Republic of China) | Legislative Yuan | 2024 | Non-compensatory | Parallel voting (superposition) | ||||||
Tajikistan | Assembly of Representatives | 2020 | Non-compensatory | Parallel voting (superposition) | ||||||
Tanzania | National Assembly | 2020 | Non-compensatory | Parallel voting (superposition) | ||||||
Thailand | House of Representatives | next election, | Non-compensatory | Parallel voting (superposition) | 2 | |||||
United Kingdom | Scotland - Scottish Parliament | Compensatory | Additional member system (AMS) | semi-proportional | ||||||
Wales - Senedd (Welsh Parliament) | Compensatory | Additional member system (AMS) | 2 | semi-proportional | ||||||
Local elections in | Compensatory | Additional member system (AMS) | ||||||||
Venezuela | National Assembly | 2020 | Non-compensatory | 1 (local districts), 400 (nationwide constituency) | Parallel voting (superposition) | 2 | ||||
Zimbabwe | National Assembly | 2018 | Non-compensatory | 1 (local districts), 10 (proportional constituencies) | Superposition | 1 |
Plurality voting refers to electoral systems in which a candidate who polls more than any other is elected. In systems based on single-member districts, it elects just one member per district and may also be referred to as first-past-the-post (FPTP), single-member plurality (SMP/SMDP), single-choice voting, simple plurality or relative majority. A system that elects multiple winners elected at once with the plurality rule and where each voter casts multiple X votes in a multi-seat district is referred to as plurality block voting. A semi-proportional system that elects multiple winners elected at once with the plurality rule and where each voter casts just one vote in a multi-seat district is known as single non-transferable voting.
Proportional representation (PR) refers to any type of electoral system under which subgroups of an electorate are reflected proportionately in the elected body. The concept applies mainly to political divisions among voters. The essence of such systems is that all votes cast – or almost all votes cast – contribute to the result and are effectively used to help elect someone – not just a bare plurality or (exclusively) the majority – and that the system produces mixed, balanced representation reflecting how votes are cast.
The additional-member system (AMS) is a mixed electoral system under which most representatives are elected in single-member districts (SMDs), and the other "additional members" are elected to make the seat distribution in the chamber more proportional to the way votes are cast for party lists. It is distinct from parallel voting in that the "additional member" seats are awarded to parties taking into account seats won in SMDs, which is not done under parallel voting.
Mixed-member proportional representation is a mixed electoral system in which votes are cast for both local elections and also for overall party vote tallies, which are used to allocate additional members to produce or deepen overall proportional representation.
First-past-the-post voting is an electoral system wherein voters cast a vote for a single candidate, and the candidate with the most votes wins the election. Analogous systems for multi-winner contests are known as plurality block voting or "block voting" systems; both FPTP and block voting are "plurality" systems in that the winner needs only a plurality of the votes and not an absolute majority. The term first-past-the-post is a metaphor from horse racing of the plurality-voted candidate winning such a race; the electoral system is formally called single-member plurality voting (SMP) when used in single-member districts, and informally called choose-one voting in contrast to ranked voting or score voting.
Parallel voting is a type of mixed electoral system in which representatives are voted into a single chamber using two or more different systems, most often first-past-the-post voting (FPTP) with party-list proportional representation (PR). It is the most common form of mixed member majoritarian representation (MMM), which is why these terms are often used synonymously with each other. In some countries, parallel voting is known as the supplementary member (SM) system, while in academic literature it is sometimes called the superposition method within mixed systems.
A referendum was held on October 10, 2007, on the question of whether to establish a mixed member proportional representation (MMP) system for elections to the Legislative Assembly of Ontario. The vote was strongly in favour of the existing plurality voting or first-past-the-post (FPTP) system.
A party-list system is a type of electoral system that formally involves political parties in the electoral process, usually to facilitate multi-winner elections. In party-list systems, parties put forward a list of candidates, the party-list who stand for election on one ticket. Voters can usually vote directly for the party-list, but in other systems voters may vote for directly individuals candidates within or across party lists, besides or instead of voting directly for parties.
Scotland uses different electoral systems for elections to Parliament, the Scottish Parliament and to local councils. A different system was also in use between 1999 and 2019 for United Kingdom elections to the European Parliament. Historically, only First Past the Post (FPTP) was used for all elections in Scotland, but this changed in 1999 both with the introduction of D'Hondt elections to the EU Parliament and the inception the same year of the devolved Scottish Parliament. Two of the devolved legislatures in the United Kingdom - the Scottish Parliament and the Senedd - use the Additional Members System (AMS). AMS has been used for every Scottish Parliament election since 1999, with the most recent being in 2021.
Electoral reform is a change in electoral systems which alters how public desires are expressed in election results.
Semi-proportional representation characterizes multi-winner electoral systems which allow representation of minorities, but are not intended to reflect the strength of the competing political forces in close proportion to the votes they receive. Semi-proportional voting systems can be regarded as compromises between forms of proportional representation such as party-list PR, and plurality/majoritarian systems such as first-past-the-post voting. Examples of semi-proportional systems include the single non-transferable vote, limited voting, and parallel voting.
An electoral system or voting system is a set of rules that determine how elections and referendums are conducted and how their results are determined. Electoral systems are used in politics to elect governments, while non-political elections may take place in business, non-profit organisations and informal organisations. These rules govern all aspects of the voting process: when elections occur, who is allowed to vote, who can stand as a candidate, how ballots are marked and cast, how the ballots are counted, how votes translate into the election outcome, limits on campaign spending, and other factors that can affect the result. Political electoral systems are defined by constitutions and electoral laws, are typically conducted by election commissions, and can use multiple types of elections for different offices.
A majoritarian electoral system is an electoral system where the candidate with the most votes takes the seat using the winner-takes-all principle and in this way provides majoritarian representation. However, there are many electoral systems considered majoritarian based on different definitions, including types of at-large majoritarian representation such as block voting or party block voting, but district-based majoritarian systems such as first-past-the-post voting (FPTP/SMP). Where two candidates are in the running, the one with the most votes will have a majority, but where there are three or more candidates, it often happens that no candidate takes a majority of the votes.
Scorporo is a partially compensatory, mixed-member majoritarian electoral system, sometimes referred to as a negative vote transfer system (NVT) whereby a portion of members are elected in single-member districts (SMDs) and a portion are elected from a list. It may be fully defined as a parallel voting system which excludes a portion of the SMD winners' votes in electing the proportional tier, to result in a more proportional outcome. The exclusion of a portion of the SMD winners' votes is what makes scorporo fundamentally different from parallel voting and somewhat closer to mixed member proportional representation, and thereby between the two in terms of proportionality. The system is only known to have been used in Italy and for a portion of the compensatory tier of the National Assembly of Hungary.
Dual-member proportional representation (DMP), also known as dual-member mixed proportional, is an electoral system designed to produce proportional election results across a region by electing two representatives in each of the region’s districts. The first seat in every district is awarded to the candidate who receives the most votes, similar to first-past-the-post voting (FPTP). The second seat is awarded to one of the remaining district candidates so that proportionality is achieved across the region, using a calculation that aims to award parties their seats in the districts where they had their strongest performances.
Rural–urban proportional representation (RUP), also called flexible district PR, is a mixed electoral system which combines the use of single- and multi-member constituencies in a lower tier and top-up seats in an upper tier to meet the different needs of both rural and urban areas, while protecting the objective of proportionality. The term was coined by Fair Vote Canada, which devised a rural–urban system with the intention of meeting the special challenges of Canada's geography, which includes wide-flung, sparsely populated areas.
The mixed single vote (MSV) or positive vote transfer system (PVT) is a mixed-member electoral system, where voters cast a single vote in an election, which used both for electing a local candidate and as a vote for a party affiliated with that candidate according to the rules of the electoral system. Unlike the more widespread mixed proportional and mixed majoritarian systems where voters cast two votes, split-ticket voting is not possible in MSV.
The mixed ballot transferable vote (MBTV) refers to a type of vote linkage-based mixed-member electoral system where a group of members are elected on local (lower) tier, for example in single-member districts (SMDs). Other members are elected on a compensatory national (upper) tier from a list and voters cast a single ballot where they may indicate their preferences separately.
Mixed member majoritarian representation (MMM) is type of a mixed electoral system combining majoritarian and proportional methods, where the disproportional results of the majoritarian side of the system prevail over the proportional component. Mixed member majoritarian systems are therefore also as a type of semi-proportional representation, and are usually contrasted with mixed-member proportional representation (MMP) which aims to provide proportional representation via additional compensation ("top-up") seats.
The next Italian general election will occur no later than 22 December 2027, although it may be called earlier as a snap election.