In political science, parallel voting or superposition refers to the use of two or more electoral systems to elect different members of a legislature. More precisely, an electoral system is a superposition if it is a mixture of at least two tiers, which do not interact with each other in any way; one part of a legislature is elected using one method, while another part is elected using a different method, with all voters participating in both. Thus, the final results can be found by calculating the results for each system separately based on the votes alone, then adding them together. A system is called fusion (no to be confused with electoral fusion) or majority bonus, another independent mixture of two system but without two tiers. Superposition (parallel voting) is also not the same as "coexistence", which when different districts in the same election use different systems. Superposition, fusion and coexistence are distinct from dependent mixed electoral systems like compensatory (corrective) and conditional systems.

Most often, parallel voting involves combining a winner-take-all system with party-list proportional representation (PR).[1] While first-preference plurality with PR is the most common pairing in parallel voting, many other combinations are possible.

The proportion of list seats compared to total seats ranges widely; for example 30% in Taiwan, 37.5% in Japan and 68.7% in Armenia.[2] Parallel voting is used in both national parliaments and local governments in Italy, Taiwan, Lithuania, Russia, Argentina, and other countries, making it among the world's most popular electoral systems.[citation needed]

## Definition

In parallel voting, voters cast two (or more) votes, one for each method the system contains.[citation needed] However, these votes do not interact in any way: the vote in one method has no effect on the calculation of seats in the other methods.

### Confusion and conflation

Under the most common form of parallel voting, a portion of seats in the legislature are filled by the single-member first-preference plurality method (FPP), while others are filled by proportional representation.[3] This sometimes leads to a hypercorrection that attempts to limit the term parallel voting to refer only to mixtures of first-past-the-post and proportional representation. Parallel voting can use other systems besides FPP, and can have any mixture of winner-take-all, semi-proportional, and proportional components.

Although the two are often mistakenly conflated, mixed-member majoritarian representation and parallel voting refer to two different things. Parallel voting refers to a rule for computing each party's representation in a legislature, which involves two voting systems operating in parallel, with one being layered (superimposed) on top of the other. By contrast, mixed-member majoritarian representation refers to the results of the system, i.e. the system retains the advantage that some parties parties get in the winner-take-all side of the system.

For this reason, parallel voting is not always mixed-member majoritarian. For example, parallel voting may use a two proportional systems like STV and list-PR and then it would not be mixed-member majoritarian, and a majority bonus system (which is not the same as parallel voting) may also be considered mixed majoritarian. In addition, some mixed-member majoritarian systems are not parallel, in that they allow for interaction (limited compensation) between the two components, as in some additional member systems.

Unlike mixed-member proportional representation, where party lists are used to achieve an overall proportional result in the legislature, under parallel voting, proportionality is confined only to the list seats. Therefore, a party that secured, say, 5% of the vote will have only 5% of the list seats, and not 5% of all the seats in the legislature.

### Representation for smaller parties

The major critique of parallel systems is that they cannot guarantee overall proportionality. Large parties can win very large majorities, disproportionate to their percentage vote.

Parallel voting systems allow smaller parties that cannot win individual elections to secure at least some representation in the legislature; however, unlike in a proportional system they will have a substantially smaller delegation than their share of the total vote. This is seen by advocates of proportional systems to be better than elections using only first-past-the-post, but still unfair towards constituents of smaller parties. If there is also a threshold for list seats, parties which are too small to reach the threshold are unable to achieve any representation, unless they have a very strong base in certain constituencies to gain individual seats.

Smaller parties are still disadvantaged as the larger parties still predominate. Voters of smaller parties may tactically vote for candidates of larger parties to avoid wasting their constituency vote. If the smaller party close to the threshold may refrain from voting for their preferred party in favor of a larger party to avoid wasting their list vote as well. In countries where there is one dominant party and a divided opposition, the proportional seats may be essential for allowing an effective opposition.

Those who favor majoritarian systems argue that supplementary seats allocated proportionally increases the chances that no party received a majority in an assembly, leading to minority or coalition governments.[citation needed] As a result, the largest parties may need to rely on the support of smaller ones in order to form a government. Those who favor proportional representation see this as an advantage as parties may not govern alone, but have to compromise. It is also argued that parallel voting does not lead to the degree of fragmentation found in party systems under pure forms of proportional representation.[4]

### Two types of representatives

Because voters have two votes, one for a constituency candidate and one for a list, there is a critique that two classes of representatives will emerge under a parallel voting system: with one class beholden to their electorate seat, and the other concerned only with their party. Some consider this as an advantage as local as well as national interests will be represented. Some prefer systems where every constituency and therefore every constituent has only one representative, while others prefer a system where every MP represents the electorate as a whole as this is reflected in the electoral system as well.

### Compared to MMP and AMS

Parallel systems are often contrasted with mixed-member proportional systems (MMP) or the additional member system (AMS). There are a unique set of advantages and disadvantages that apply to these specific comparisons.

A party that can gerrymander local districts can win more than its share of seats. So parallel systems need fair criteria to draw district boundaries. (Under MMP a gerrymander can help a local candidate, but it cannot raise a major party’s share of seats, while under AMS the effects of gerrymandering are reduced by the compensation)

Japan, and subsequently Thailand and Russia adopted a parallel system to provide incentives for greater party cohesiveness.[5] The party is sure to elect the candidates at the top of its list, guaranteeing safe seats for the leadership. By contrast, under the MMP or AMS system a party that does well in the local seats will not need or receive any compensatory list seats, so the leadership might have to run in the local seats.

Certain types of AMS can be made de facto parallel systems by tactical voting and parties using decoy lists, which (other) MMP systems generally avoid. This specific type of tactical voting does not occur in parallel voting systems as there is no interaction between its systems to exploit in a way that makes it irrelevant. However, other types of tactical voting (such as compromising) are more relevant under parallel voting, than under AMS, and are virtually irrelevant under MMP.[citation needed] Tactical voting by supporters of larger parties in favor of allied smaller parties close to a threshold, to help their entry to parliament are a possibility in any parallel, AMS or MMP system with an electoral threshold.

Parallel systems support the creation of single-party majorities more often than MMP or AMS systems. This may be seen as a positive or a negative depending on the view of the voter.

### Representation for smaller parties

The major critique of parallel systems is that they cannot guarantee overall proportionality. Large parties can win very large majorities, disproportionate to their percentage vote.

Parallel voting systems allow smaller parties that cannot win individual elections to secure at least some representation in the legislature; however, unlike in a proportional system they will have a substantially smaller delegation than their share of the total vote. This is seen by advocates of proportional systems to be better than elections using only first-past-the-post, but still unfair towards constituents of smaller parties. If there is also a threshold for list seats, parties which are too small to reach the threshold are unable to achieve any representation, unless they have a very strong base in certain constituencies to gain individual seats.

Smaller parties are still disadvantaged as the larger parties still predominate. Voters of smaller parties may tactically vote for candidates of larger parties to avoid wasting their constituency vote. If the smaller party close to the threshold may refrain from voting for their preferred party in favour of a larger party to avoid wasting their list vote as well. In countries where there is one dominant party and a divided opposition, the proportional seats may be essential for allowing an effective opposition.

Those who favour majoritarian systems argue that supplementary seats allocated proportionally increases the chances that no party received a majority in an assembly, leading to minority or coalition governments.[citation needed]; the largest parties may need to rely on the support of smaller ones in order to form a government. Those who favour proportional representation see this as an advantage as parties may not govern alone, but have to compromise. It is also argued that parallel voting does not lead to the degree of fragmentation found in party systems under pure forms of proportional representation.[6]

### Two types of representatives

Because voters have two votes, one for a constituency candidate and one for a list, there is a critique that two classes of representatives will emerge under a parallel voting system: with one class beholden to their electorate seat, and the other concerned only with their party. Some consider this as an advantage as local as well as national interests will be represented. Some prefer systems where every constituency and therefore every constituent has only one representative, while others prefer a system where every MP represents the electorate as a whole as this is reflected in the electoral system as well.

### Compared to MMP and AMS

Parallel systems are often contrasted with mixed-member proportional systems (MMP) or the additional member system (AMS). There are a unique set of advantages and disadvantages that apply to these specific comparisons.

A party that can gerrymander local districts can win more than its share of seats. So parallel systems need fair criteria to draw district boundaries. (Under MMP a gerrymander can help a local candidate, but it cannot raise a major party’s share of seats, while under AMS the effects of gerrymandering are reduced by the compensation)

Japan, and subsequently Thailand and Russia adopted a parallel system to provide incentives for greater party cohesiveness.[7] The party is sure to elect the candidates at the top of its list, guaranteeing safe seats for the leadership. By contrast, under the MMP or AMS system a party that does well in the local seats will not need or receive any compensatory list seats, so the leadership might have to run in the local seats.

Certain types of AMS can be made de facto parallel systems by tactical voting and parties using decoy lists, which (other) MMP systems generally avoid. This specific type of tactical voting does not occur in parallel voting systems as there is no interaction between its systems to exploit in a way that makes it irrelevant. However, other types of tactical voting (such as compromising) are more relevant under parallel voting, than under AMS, and are virtually irrelevant under MMP.[citation needed] Tactical voting by supporters of larger parties in favour of allied smaller parties close to a threshold, to help their entry to parliament are a possibility in any parallel, AMS or MMP system with an electoral threshold.

Parallel systems support the creation of single-party majorities more often than MMP or AMS systems, this may be a positive or a negative depending on the view of the voter.

## Use

### Current use

Parallel voting is currently used in the following countries:[8]

Country Body Candidates elected by
Members elected in constituencies % System Members elected by proportional representation % System Other %
Andorra General Council 14 (2 seats per constituency) 50% PBV 14 50% List PR
Argentina Legislature of Córdoba Province 26 37% FPTP 44 63% List PR
Legislature of Río Negro Province 24 (3 seats per constituency) 52% List PR 22 48% List PR
Chamber of Deputies of San Juan 19 53% FPTP 17 47% List PR
Chamber of Deputies of Santa Cruz 14 58% FPTP 10 42% List PR
Guinea National Assembly 38 33% FPTP 76 67% List PR (Hare quota)
Japan House of Representatives 289 62% FPTP 176 38% List PR
House of Councillors 147 60% SNTV 98 40% List PR
Kazakhstan Majilis 69 30% FPTP 69 70 List PR
Kyrgyzstan Supreme Council 36 40% FPTP 54 60% List PR
Lithuania Seimas 71 50% TRS 70 50% List PR (largest remainder method): open lists
Mexico Chamber of Deputies 300 60% FPTP 200 (40 seats per regions) 40% List PR (Hare quota)
Mongolia[9] State Great Khural 78 62% BPV 48 38% List PR: closed lists
Nepal House of Representatives 165 60% FPTP 110 40% List PR: closed lists
Philippines House of Representatives 253 80% FPTP 63 20% List PR (Hare quota): closed lists
Russian Federation State Duma 225 50% FPTP 225[10][11] 50% List PR (Hare quota): closed lists
Senegal National Assembly 105 64% FPTP 60 36% List PR (largest remainder method)
South Ossetia 17 50% FPTP 17 50% List PR
Taiwan (Republic of China) Legislative Yuan 73 65% FPTP 34 30% List PR 6 for indigenous citizens 5%
Tajikistan Assembly of Representatives 41 65% TRS 22 35% List PR
Tanzania[12] National Assembly 264 67% FPTP 113 (women-only lists) 29% List PR 5 indirectly elected
+ 1 attorney general
+ 10 nominated by President
4%
Thailand House of Representatives 400 80% FPTP 100 20% List PR
Venezuela National Assembly 113[citation needed] 68% FPTP 51[citation needed] 31% List PR 3 for indigenous 2%
Country Body Members elected in constituencies % System Members elected by winner-take-all % System Other %
Realm of New Zealand Niue Assembly 14 70% FPTP 6 30% Plurality block voting (BV)
British overseas territories Anguilla House of Assembly 7 54% FPTP 4 31% Plurality block voting (BV) 2 ex officio 15%
Turks and Caicos Islands House of Assembly 10 48% FPTP 5 24% Plurality block voting (BV) 4 appointed + 2 ex officio 28%
British Virgin Islands House of Assembly 9 60% FPTP 4 27% Plurality block voting (BV) 2 ex officio 13%

#### Philippines

The Philippines' electoral system for Congress is an exceptional case. Political parties running for party-list seats are legally required to be completely separate from those running in constituency seats. Furthermore, political parties are capped at 3 seats (out of 61). As a result, the mixed-member system utilized in the Philippines is not representative at all of the share of the vote that "normal" political parties obtain (even amongst mixed-member majoritarian systems), let alone for those in full proportional representation systems.

### Hybrid use and similar systems

• Hungary's National Assembly uses a system where the parallel voting component shares a pool of seats (93) with the vote transfer system and with the minority list seats with a reduced entry threshold. This means the number of seats effectively assigned proportionally based on the parallel party list votes is unknown/unknowable before the election takes place.[13]
• Italy: Starting with the 2018 election, both houses of the Italian parliament are elected using a system similar to parallel voting. 62.5% of the seats are assigned proportionally to party lists; party lists are also linked in coalitions supporting constituency candidates running for the remaining 37.5% of the available seats, who are elected by means of a first-past-the-post system. Electors have a single vote with two-fold effects for a party list (proportional) and its associated local candidate (majoritarian). Split-ticket voting is not allowed, a voter may mark their ballots only next to a list, a candidate, or a list and a candidate associated with it and all of these votes has the same effect. If a voter marks a candidate not associated with the list they marked, like voters may under parallel voting, the vote is invalid under the Italian system.
• Jersey (UK)
• Monaco
• Mexico: In contrast to the parallel voting system for the Chamber of Deputies, for electing the Chamber of Senators (upper house), a single (party list) vote is used similarly to the Italian system. However, constituencies have 3 seats with a type of limited (party block) voting being used: 2 seats are given to the largest party and 1 to the second largest party. Party-list PR is used for the nationwide seats.
• Pakistan
• Seychelles

### Proposals for use

In New Zealand, the Royal Commission on the Electoral System reviewed the electoral system in 1985-86 and considered parallel voting as a possible replacement for the single-member plurality (SMP) system in use at the time.

The commission came to the conclusion that parallel voting would be unable to overcome the shortcomings of New Zealand's previous SMP system. The total seats won by a party would likely remain out of proportion to its share of votes—there would be a "considerable imbalance between share of the votes and share of the total seats"—and it would be unfair to minor parties (who would struggle to win constituency seats).[18] In the indicative 1992 electoral referendum, parallel voting was one of four choices for an alternative electoral system (alongside MMP, AV and STV), but came last with only 5.5 percent of the vote. An overwhelming majority of voters supported MMP, as recommended by the Royal Commission, and the system was adopted after the 1993 electoral referendum.

In another referendum in 2011, 57.77% of voters elected to keep current the MMP system. Among the 42.23% that voted to change to another system, a plurality (46.66%) preferred a return to the pre-1994 SMP system. Parallel voting was the second-most popular choice, with 24.14% of the vote.[citation needed]

## References

1. ^ "Parallel —". aceproject.org. Retrieved 2022-04-21.
2. ^ Reynolds et al (2008), Electoral System Design: The New International IDEA Handbook, Sweden: International Institute for Democracy and Electoral Assistance, pg. 104
3. ^ Royal Commission on Electoral Systems (1986), Report of the Royal Commission on the Electoral System: towards a better democracy, Wellington N.Z.: Government Printing, pg. 33.
4. ^ Reynolds et al (2008), Electoral System Design: The New International IDEA Handbook, Sweden: International Institute for Democracy and Electoral Assistance, pg. 112
5. ^
6. ^ Reynolds et al (2008), Electoral System Design: The New International IDEA Handbook, Sweden: International Institute for Democracy and Electoral Assistance, pg. 112
7. ^
8. ^ Reynolds et al. (2008), Electoral System Design: The New International IDEA Handbook, Sweden: International Institute for Democracy and Electoral Assistance, pg. 30–33
9. ^ Smith, Marissa. "Parliamentary Elections 2024: Yet Another New Election System". Mongolia Focus. University of British Columbia. Retrieved 2024-04-19.
10. ^ Herszenhorn, David M. (2013-01-03). "Putin Orders New System for Russian Parliamentary Elections - NYTimes.com". The New York Times. Retrieved 2014-09-09.
11. ^ Since the 2016 election, and from 1993 to the 2003 election.
12. ^ "Art. 66, Constitution of Tanzania". Constitute Project.
13. ^ Political Capital (2012) The new electoral law in Hungary - In-depth analysis http://www.valasztasirendszer.hu/wp-content/uploads/PC_ElectoralSystem_120106.pdf
14. ^ Gallagher 2011, p. 185; Gallagher 2014, p. 18.
15. ^ Lublin, David. "Albania". Election Passport. American University. Retrieved 24 March 2016.
16. ^ Election Rigging and How to Fight It Journal of Democracy - Volume 17, Number 3, July 2006, pp. 138-151.
17. ^ "Key Points of Newly Adopted Constitution". Civil Georgia. 27 September 2017. Retrieved 27 September 2017.
18. ^ Royal Commission on Electoral Systems (1986), Report of the Royal Commission on the Electoral System: towards a better democracy, Wellington N.Z.: Government Printing, pg. 39.