Vote linkage
The vote linkage or vote transfer system is type of compensatory mixed electoral system, where votes may be transferred across multiple tiers of an electoral system, in order to avoid wasted votes - in contrast to the more common proportional representation|seat linkage compensatory system]. It often presupposes and is related to the concept of the mixed single vote, which means that the same vote can be used in multiple tiers of an electoral system and that a vote for a local candidate may automatically count as a vote for the candidate's party or the other way around. Voters usually cast their single vote for a local candidate in a single-member district and then all the wasted votes from this lower tier are added to distribute seats between upper tier candidates, typically national party lists.
Partially compensatory multi-tier vote linkage is an equivalent of the indirect single transferable vote among multi-tiered electoral systems. A related concept is seat linkage, where it is not the votes used in one tier that connect two tiers, but the number of seats a party achieved on the lower tier that is taken into account. A vote linkage system, when applied in a compensatory way takes into account the number of votes that were effective or wasted in the lower tier and takes this into account in the apportionment of the upper tier.
Vote linkage systems currently or formerly used for various national or local elections in Germany, Hungary and Italy have been sometimes described as mixed-majoritarian, or a unique system between MMM and MMP. Some supermixed systems use vote linkage together with parallel voting in a two-vote setup, where split ticket voting is allowed. How proportional the outcome depends on many factors including the vote transfer rules, such which votes are recounted as party list votes, and other parameters used in the system. The vote linkage system originates from Germany and is currently used in Hungary. A version called scorporo was also used in Italy from 1993 to 2005.
Terminology
may use vote linkage compensation, meaning not all, but only 'wasted' votes get transferred as list votes to the other tier. Some uncommon, supermixed systems use of MSV may add or subtract the discounted list results to establish a vote linkage based element of compensation into system that would otherwise be categorised as parallel voting. Either type of system is misleadingly known in Hungarian as a "fractional vote recounting system", however, there are no fractional votes used in any variation, the name merely alluding to only a fraction of votes being "recounted" as list votes.The third type of mixed single vote system is the single vote equivalent of parallel voting, which uses the same vote on both the majoritarian and proportional tiers. This makes such systems non-compensatory, falling under the superposition type of mixed systems identified by Massicotte & Blais.
Positive and negative vote transfer
The first recorded mixed vote transfer systems have been under the "losers plus surplus" model, therefore, they inherently included "winner compensation". Under later definitions of certain sources, this model would also be retroactively a "negative vote transfer system" despite not using any votes with negative transfer value. The confusion stems from the terms "positive" and "negative vote transfer system" being coined based on the systems in use in the 1990s and early 2000s in Hungary and Italy and the inconsistent terminology of sources on these niche variants. While all the Hungarian versions primarily transferred votes with a positive value and the votes transferred were almost exclusively in compensation for losing candidates, the Italian models of scorporo operated only with a negative value and deducted all or a part of votes cast for local winners.In one view, positive vote transfer means vote transfer with only positive votes value, with or without winner compensation. This means that either only the positive transfer votes are used on the list tier to apportion seats, or they are added to other list votes. Negative vote transfer systems, meanwhile use the opposite principle, they subtract exactly those votes, which the equivalent positive vote transfer would not transfer. In this way, these systems rely on negative value winner compensation, which is their most important property that determines how they can be manipulated.
In some sources, the Hungarian model of "losers only" has been labeled "positive vote transfer", under this view the Italian Senate model, despite using only negative transfer votes would also be PVT, since it operates under the same "losers only" principle. Conversely "negative vote transfer" means not only the Italian Chamber model of scorporo is, but the original German variants and the current Hungarian electoral systems for national elections. A third term of "direct vote transfer" has been used for vote transfer systems without compensation. This view has been criticized for using unintuitive terminology and not including models of winner compensation other than the surplus votes compared to the second place candidate. This article uses the former view to maintain consistency and to show the significance of positive/negative transfers on manipulation more intuitively.
Controversy on winner compensation
Though the original vote linkage systems used the "losers plus surplus" model, the systems established in Hungary only used votes cast for losing candidates on the compensatory tier of the electoral systems. For this reason, when the system for the National Assembly was changed by the governing parties before the 2014 election, the introduction of transferring surplus votes was a novel element in the system. This element was soon called "winner compensation", who claimed it was effectively a majority bonus. Together with other criticisms of the change this was viewed as a thinly veiled attempt to benefit the parties who created the system, without meaningful consultation of the opposition.Similar proportional systems
Some non-mixed systems, which use multi-member constituencies either on their single tier or also on their lower tier use vote linkage. An example is the national remnant system of Weimar Germany. This system used an absolute quota instead of plurality to elect candidates. With the fixed quota and a changing population, this meant a flexible parliament size.The vote transfer to party list is the mixed single vote equivalent to indirect single transferable voting, while the direct equivalent to the single transfer vote is the mixed ballot transferable vote.
Advantages and disadvantages
The features of vote linkage compensatory systems are similar to those of comparable parallel voting or mixed-member proportional systems, depending on which systems does the result more resemble. As mixed systems they usually inherit properties of their subsystems, in case of the most commonly used vote linkage systems, these are first preference plurality and closed list PR. Single vote variants also suffer from the disadvantages of the mixed single vote, however in certain systems this also gives robusticity against strategic manipulation.Representation for smaller parties
Vote linkage systems generally give greater representation to smaller parties than parallel voting with the same amount of list seats, but usually not as much as comparable seat linkage systems - they usually cannot guarantee overall proportionality. Large parties can win very large majorities, disproportionate to their percentage vote, especially when vote linkage is employed in a supermixed system combined with parallel voting. In Hungary for example, in last 3 elections have resulted in a 2/3 supermajority of seats for the most popular list from at low as 45% of the vote in 2014.Two types of representatives
Because some candidates are elected from constituencies and some from a list, there is a critique that two classes of representatives will emerge under any mixed system, including vote linkage ones: 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, while a vote linkage mixed system provides a compromise between these two views.Compared to seat linkage and parallel voting
Vote linkage systems can be compared to the mixed-member proportional systems / additional member system and the common form of mixed-member majoritarian representation, parallel voting.Like in parallel voting, 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.
Seat linkage and vote linkage systems both suffer from different potential manipulation strategies arising from their compensatory component, which the following table shows. Parallel voting does not suffer from these by definition, since the worst case of strategic manipulation reverts compensatory systems to parallel voting.
Use
West Germany
The first recorded use of a vote-transfer based mixed system was in British occupied West Germany. German opposition to a purely winner-take-all system like first-past-the-post, that the British preferred, necessitated a compromise. The vote transfer system which was of the "losers plus surplus model" included winner compensation and the majority of seats were won in single-member district would mostly keep the result as close to first-past-the-post as possible, while allowing for some compensatory representation of other parties. Since then, all German states that used such a system have changed either to either the seats linkage-based MMP or a pure party-list proportional system.Hungary
A re-emergence of the vote linkage mixed system started in the turn of the 1990s, when politicians in Hungary, in transition to a democracy, were deliberating what electoral system to adopt. In this transition many aspects of constitutional and governmental structure were adopted from Germany. For the National Assembly, one of the most complicated supermixed systems was developed as a compromise between a winner-take-all and a purely proportional system. This system used a modified two-round system in single-member districts, regional lists and a small number of national compensatory seats based on the votes cast for losers in the local districts. The system, however, had some small negative value winner compensation from the party-list PR of the regional multi-member districts as well. Despite the sometimes highly disproportionate results, the system has often been mistaken for mixed-member proportional representation both inside and outside of Hungary, especially since it is common knowledge that it was derived from 'the' German system. The losers only model because the predominant form of mixed system known and used in Hungary, with similar systems designed for local elections.The system for the National Assembly was in use until the elections of 2014, since which a simplified, but much more distinctly mixed-member majoritarian system is used.
National Assembly (general elections)
elections use a positive vote transfer system, which also partially 'compensates' parties of winning candidates.The compensatory tier of the National Assembly of Hungary is allocated to parties crossing a national 5% threshold. Votes of losing candidates as well as surplus votes of winning candidates are added to the list vote, making it a positive vote transfer system. Surplus votes are calculated by subtracting the result of the second-place candidate plus 1 from the result of the first place candidate, making the system similar to the Italian Chamber model of scorporo. However, because there are effectively no votes transferred with a negative value, the system is not subject to the same decoy list tactics as scorporo is. Instead, when decoy lists were mentioned in the context of the Hungarian system, it was in reference to the proliferation of unknown parties with similar names to known parties, fielding decoy lists allegedly intended to confuse voters.
Local elections
Local elections in municipalities and districts in the capital with a population over 10 000 use a mixed single vote with positive vote transfer, where only votes for losing candidates are transferred to the compensatory tier. The vote transfer takes place based on the party affiliation of the local candidates and seats are allocated proportionally based on the transferred votes.- Up to 25 000 residents 8 members are elected in SMDs and 3 members on the compensatory tier
- Up to 50 000 residents 10 members are elected in SMDs and 4 members on the compensatory tier
- Up to 75 000 residents 12 members are elected in SMDs and 5 members on the compensatory tier
- Up to 100 000 residents 14 members are elected in SMDs and 6 members on the compensatory tier
- Over 100 000 residents, the number of SMDs increases by 1 after every additional 10 000 residents, while the number of compensatory seats increases by 1 after every additional 25 000 residents.
Because of the comparatively few compensatory seats, the system does not guarantee proportional results and commonly underrepresents smaller parties, however theoretically, it could also underrepresent larger parties compared to a list PR system.
Italy
A negative vote transfer system called scorporo was in force for elections to the bicameral Parliament of Italy based on Law 277/1993 from 1993 to 2005. Under this system, members could be elected in two ways:- 75% of elected members were elected in single member districts using first-past-the-post voting.
- 25% of elected members were elected on list basis based on the proportion of the votes received by the party, with the exclusion of a proportion of any first-placed winner's votes.
Senate
- List seats were calculated at the regional level.
- All votes for winning candidates were excluded from the list allocation.
- No threshold was applied for list seats.
- The SMD vote and the list vote were linked limiting the use of decoy lists.
Chamber of Deputies
- The list seats were calculated at the national level.
- The number of SMD winner's votes excluded from the list vote was equal to the second place candidate's vote total, representing the number of votes needed to elect the winner in the SMD.
- A 4% threshold was established for parties to qualify for the list seats.
- The local vote and list vote were not tied to each other, thereby providing an incentive for decoy lists.
Abolition
In the 2001 Italian general election, one of the two main coalitions, linked many of their constituency candidates to a decoy list for the proportional component, under the name Abolizione Scorporo. This list was not designed to win proportional seats, but only to soak up constituency votes for House of Freedoms, enabling them to win a larger share of the proportional list seats than they would be entitled to if all candidates were linked other House of Freedoms parties. This intentionally undermined the compensatory nature of the electoral system. As a defensive move, the other coalition, The Olive Tree, created their own decoy list under the name Paese Nuovo. This was facilitated by the fact that this particular scorporo system allowed the single-member constituency vote and the proportional list vote not to be linked. Decoy lists are a common issue in all compensatory and pseudo-compensatory systems, and this was not a unique problem for scorporo. Due to Silvio Berlusconi's opposition to the system, Italy changed to a majority bonus system in 2005.Proposals, mixed ballots and hybrids
Some properties of vote linkage, especially robusticity against certain types of tactical manipulation have led to social choice theorists to develop variations and hybrid using vote linkage. Golosov argued for the use of vote linkage via mixed single vote, developing a system which requires less compensatory seats but adequate proportionality as compromise alternative to conventional MMP systems. The mixed ballot transferable vote was proposed as a preferential variant of the mixed single vote where voters may indicate their preferences separately, and the original proposal also explores methods to make the system relatively proportional.A system using a mixed single vote in dual member districts called dual-member proportional has been proposed for Canada by Sean Graham. DMP uses both vote transfer and seat linkage.
An open list variant of MMP has been proposed by Jameson Quinn which uses a mixed ballot and vote linkage combined with classical seat linkage.
- If a ballot supports the winner in the local district, the list part of that ballot is counted for the party of that local winner.
- If a ballot supports two different parties on its two halves, and exactly one of those two parties is nonviable, then it is counted as if both parts of that ballot supported the viable party. (This is inspired by transferring ballots in STV, and reduces the chances of "wasted/sub-threshold" voting power.