Mixed electoral system

A mixed electoral system is one that uses different electoral methods for different seats in a multi-winner election. Most often, this involves a winner-take-all (usually single-winner and regional) component combined with a proportional, partisan component. The results of the combination may be mixed-member proportional (MMP), where the overall results of the elections are proportional, or mixed-member majoritarian (MMM), in which case the overall results are semi-proportional, retaining disproportionalities from the majoritarian component. Systems that employ more than two methods of combinations are called supermixed.

It has become an accepted view that mixed methods are more than than just the sum of their parts. From a political science point of view, they are treated as their own category or categories (MMP, MMM, etc.) for their effect on voter behaviour and party systems. From a social choice view, some mixed methods are independent combinations of non-mixed methods, therefore can be analysed just by their parts, while others are dependent. Especially dependent combinations have their own mechanisms which make them different and may introduce additional tactical voting and strategic nomination, and therefore vulnerability to manipulation.

Types of mixed systems

Types of combinations

Dependent

Two basic forms of dependent combinations are conditional and corrective.

Comparison of most common types of two-tier mixed systems by number of votes and compensation

Independent

• Superposition
  • Parallel voting
• Fusion
• Coexistence

  

  A diagram of a coexistence based mixed electoral system combining first-past-the-post and party-list proportional representation.

Mixed-member majoritarian and mixed-member proportional

Mixed-member majoritarian

• Typically done by parallel voting: the regional system and the partisan system is done completely independently or by with insufficient compensation.
• Electoral systems with a bonus or jackpot (promoting a majority in the assembly) fall into the mixed-member majoritarian (semi-proportional) type. They may be compensatory (jackpot) or non-compensatory (bonus). Bonuses can help the most popular party or alliance win a majority of the seats with a minority of the votes, similarly to winner-take-all systems. However, PR is used to distribute the rest of seats (sometimes only among the opposition parties, hence, compensatory) and optionally within the governing alliance.

Mixed-member proportional

• Mixed-member proportional
• Dual Member Mixed Proportional is similar to a mixed compensatory with dedicated to dual-member (two seat) districts where the partisan candidate is elected. It tries to solve some of the regional and partisan issues by having dual member constituencies where the second candidate is elected from the list of runner ups. The party list being decided by the runner ups removes the partisan vote and its associated increase in partisanship. This system is a way to combined multi-member systems and mixed member systems. This is one of the all around best systems which restricts it self to a single plurality vote. Because of this, vote splitting still exists but is largely mitigated after the fact by the method of choosing the runner up. Essentially, the second candidate will be chosen to attempt to fulfill Proportional Representation and minimise vote splitting.

Number of votes

Double vote

Most mixed systems allow voters to cast separate votes for different formulas of the electoral system, including:

• Parallel voting (superposition with two votes)
• Most MMP systems
• AV+ (the first vote is ranked)

Hare Mixed systems

Another type of mixed system attempts to increase proportional representation through allowing voters to vote outside of their single member district district. There are many variations but the basic strategy is having a regional system which passes some information from one region to another. These are commonly referred to as Hare Mixed System because this was originally proposed by Sir Thomas Hare in 'Treatise on the Election of Representatives'. His system is one of the oldest (1859) and initially well-accepted systems to replace SMP. It is a combination of single regional constituencies with instant run-off ballots. The twist of the Hare system is to let people vote in constituencies other than their own. Or as stated by John Stuart Mill in Considerations of Representative Government where he expressed great favour for the Hare system

The votes would, as at present, be given locally; but any elector would be at liberty to vote for any candidate, in whatever part of the country he might offer himself. Those electors, therefore, who did not wish to be represented by any of the local candidates, might aid by their vote in the return of the person they liked best among all those throughout the country who had expressed a willingness to be chosen. This would so far give reality to the electoral rights of the otherwise virtually disfranchised minority.

This brilliant solution to representation is also its downfall. The constant changing of regional boundaries to ensure Balanced Representation is just one example. Another is that game theoretic reasons lead a voter to have to rank each candidate in the country. These logistical complications make the system prohibitively impractical even before considering the issues with instant run-off given above.

A modern version of this is Local PR which restricts the voter from voting in all regions to a predefined cluster. This cluster is then treated as a multi-member district where the Single transferable Vote algorithm is run.

List of countries using mixed systems

Superposition (parallel voting)

• Andorra (PBV and list PR)
• Argentina (some provinces)
• Georgia
• Guinea
• Italy (no ticket splitting allowed)
• Japan
• Kazakhstan
• Kyrgyzstan
• Lithuania (TRS and list PR)
• Monaco (PBV and list PR)
• Philippines
• Russia
• Senegal
• Seychelles
• Taiwan
• Tajikistan
• Thailand
• Venezuela
• Zimbabwe

Seat linkage compensatory ("MMP")

• Bolivia
• Germany (most state parliaments)
• Lesotho (mixed single vote)
• New Zealand
• Scotland
• South Africa (on local level)

Supermixed

• Armenia (majority-minority jackpot)
• Djibouti (majority jackpot)
• Greece (majority bonus")
• Hungary (superposition and vote linkage)
• Mexico (superposition with conditional seat linkage)
• South Korea (superposition with seat linkage)

Other

• Pakistan
• Tanzania

External links

ACE Electoral Knowledge Network

This page uses Creative Commons Licensed content from Wikipedia (view authors).. Portions derived from "Mixed electoral system" revision 1250149740.