Scorporo

Scorporo (Italian: [ˈskɔrporo], lit. 'parceling out') is a partially compensatory, mixed-member majoritarian electoral system, sometimes referred to as a negative vote transfer system^[1] (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 (up to 100%) 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 the additional member system in the UK (a form of mixed-member proportional representation) in theory. However, the design proved particularly susceptible to the decoy list strategy, and as a result by 2001 had devolved into a de facto parallel voting system. The scorporo method is only known to have been used in Italy, but a similar version is in used for the National Assembly of Hungary.

Use in Italy

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).

Abuse in the 2001 Italian Chamber of Deputies election

Symbols of the two liste civette

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).

The decoy lists were extremely successful. Between them, candidates linked to the decoy lists won 360 of the 475 constituency seats, more than half of the total of 630 seats in the Chamber of Deputies. Meanwhile, the decoy lists won a combined total of less than 0.2% of the proportional part of the vote. For the two main coalitions, their vote totals in the proportional component were essentially unaffected by the constituency votes, enabling them to win far more proportional seats than the system was designed for. In the case of Forza Italia (a party within House of Freedoms), the tactic was so successful that it did not have enough candidates in the proportional component, and its list exhausted before it could be awarded all the seats it had won, ultimately missing out on 12 additional seats.

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.

Abolition

Due to Silvio Berlusconi's opposition to the system, Italy changed to a majority bonus system in 2005.^{[citation needed]}

In 2018, parallel voting was brought back by the Rosatellum law.^[2]

References

^ Ferrara, F (2004). "Electoral coordination and the strategic desertion of strong parties in compensatory mixed systems with negative vote transfers". Electoral Studies. 23 (3): 391–413. doi:10.1016/S0261-3794(03)00028-3.
^ "Il Rosatellum bis è legge dello Stato: via libera definitivo al Senato con 214 sì". Repubblica.it. 2017-10-26. Retrieved 2018-03-04.

[1] Ferrara, F (2004). "Electoral coordination and the strategic desertion of strong parties in compensatory mixed systems with negative vote transfers". Electoral Studies. 23 (3): 391–413. doi:10.1016/S0261-3794(03)00028-3.

[2] "Il Rosatellum bis è legge dello Stato: via libera definitivo al Senato con 214 sì". Repubblica.it. 2017-10-26. Retrieved 2018-03-04.

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