Draft:Vote linkage mixed system

The vote linkage or (multi-tier) vote transfer system is type of mixed electoral system, where votes may be transferred across multiple tiers of an electoral system, in contrast to seat linkage systems (commonly known as additional member systems or MMP). It often presupposes and is related to the concept of the mixed single vote, which means that the same vote can be use 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. However, even vote linkage systems making use of the mixed single vote may not necessarily use only one vote, but in this case at least one of the votes be a mixed single vote. Voters usually cast their single vote for a local candidate in a single-member district (SMD) 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 (except for the mixed ballot transferable vote versions, which are multi-tier equivalents to STV). A related concept is seat linkage, where its 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. In contrast, 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 used for various national or local elections in Germany, Hungary and Italy have been described as neither mixed-majoritarian (commonly achieved by parallel voting) or mixed proportional (seat linkage), but a unique system between the two. Some supermixed systems use vote linkage together with parallel voting (superposition) in a two vote setup, where split ticket voting is allowed. How proportional the outcome is depends on many factors including the vote transfer rules, such which votes are recounted as party list votes, and other parameters (e.g. the number of list seats) used in the system. The vote linkage system originates from Germany and is currently used in Hungary. A version called scorporo was was also used in Italy from 1993 to 2005.

Mechanism

Mixed single vote systems 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.

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.

Party			Popular vote	District results			Transfer votes without winner compensation		Vote transfer system without winner compensation		Vote transfer system with compensation
				Party A strongholds	Party B strongholds	Seats	Party A strongholds	Party B strongholds	list seats	total	list seats	total
		Party A	41%	45%	33%	40	-	33%
		Party B	30%	25%	40%	20	25%	-
		Party C	25%	25%	25%	0	25%	25%
		Party D	4%	5%	2%	0	5%	2%
TOTAL			100%	100%	100%	100	55%	66%

Compared to other mixed systems

Party			Popular vote	District results			Vote transfer system without winner compensation		Seats under parallel voting - no compensation (mixed-member majoritarian system)		Seats under single vote seat linkage compensation (mixed-member proportional system)
				Party A strongholds	Party B strongholds	Seats	list seats	total	list seats	total	list seats	total
		Party A	41%	45%	33%	40			16	56		41
		Party B	30%	25%	40%	20			12	32		30
		Party C	25%	25%	25%	0			10	10		25
		Party D	4%	5%	2%	0			2	2		6
TOTAL			100%	100%	100%	100			40	100	40	100

Compensatory mixed systems
	single vote systems	dual vote systems
Seat linkage	mixed single vote, top-up versions (MSV) single vote MMP (Denmark) single vote AMS (Bolivia, Lesotho)	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) Hungarian PVT/MSV (local elections) Romanian PVT/MSV system (2008–2012)	Supermixed: Parallel voting+PVT (Hungary) negative vote transfer/scorporo (Italy, 1993–2005)
	Others systems:
	dual-member proportional (DMP)	mixed ballot transferable vote (MBTV)
Non-compensatory mixed systems
	single vote systems	dual vote systems
No linkage	mixed single vote, unlinked versions (MSV) single vote parallel voting (Tanzania, Seychelles)	parallel voting
Vote linkage	mixed single vote, superposition Italian variant (Rosatellum)	-

Use

Hungary

Main article: Electoral system of Hungary

National Assembly (general elections)

National Assembly elections use a positive vote transfer system, which also partially compensates winning candidates.

The compensatory tier of the National Assembly of Hungary (which follows a type of parallel voting with an additional compensatory systems) 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 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 (and decoy spoiler candidates) allegedly intended to confuse voters.

The former, three-tier system also used positive transfer votes for losing candidates' votes in the first round of single district voting and each party's totals were further augmented by "any wasted" votes from the regional list-tier elections. The system used for local elections does not use list votes, only positive transfer votes of losing candidates.

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.

For the 2014 and 2018 elections, General Assembly of Budapest was elected by a kind of double simultaneous vote, in that the 23 directly elected mayors of the districts and 9 members elected from compensation-lists of parties based on the votes cast for the mayoral candidates. (Budapest mayor candidates and district mayor candidates can be listed on compensation-lists). For the 2024 election, the system was reverted to a direct election using party-list

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

Main article: Scorporo

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 (SMDs) 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 (using the D'Hondt method), with the exclusion of a proportion of any first-placed winner's votes.

The system was subject to the following specific rules for each chamber:

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 (mixed single vote) limiting the use of decoy lists (see below).

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 (i.e. non-wasted votes).
• 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 (see below).

Abolition

In the 2001 Italian general election, one of the two main coalitions (the House of Freedoms, which opposed the Scorporo system), linked many of their constituency candidates to a decoy list (lista civetta) for the proportional component, under the name Abolizione Scorporo (Abolish 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 (New Country). 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.

See also

• Additional member system
• Scorporo or negative vote transfer systems
• Semi-proportional representation
• Double simultaneous vote (DSV), is a related system, in which a single vote is used for multiple separate elections at the same time (for an assembly and a president), not a single, mixed election
• List of electoral systems by country