Proportional representation
Friday, 04 October 2019
(Continued from Lastweek)
In the FairVote plan for STV (which FairVote calls choice voting) for the US House of Representatives, three- to five-member super-districts are proposed. In Professor Mollison's plan for STV in the UK, four- and five-member districts are used, with three and six as necessary to fit existing boundaries.

Minimum threshold
The minimum threshold is the minimum vote required to win a seat. The lower the threshold, the higher the proportion of votes contributing to the election of representatives and the lower the proportion of votes wasted.
All electoral systems have thresholds, either formally defined or as a mathematical consequence of the parameters of the election.
A formal threshold usually requires parties to win a certain percentage of the vote in order to be awarded seats from the party lists. In Germany and New Zealand (both MMP), the threshold is 5% of the national vote but the threshold is not applied to parties that win a minimum number of constituency seats (three in Germany, one in New Zealand). Turkey defines a threshold of 10%, the Netherlands 0.67%.Israel has raised its threshold from 1% (before 1992) to 1.5% (up to 2004), 2% (in 2006) and 3.25% in 2014.
In STV elections, winning the quota (ballots/(seats+1)) of first preference votes assures election. However, well regarded candidates who attract good second (and third, etc.) preference support can hope to win election with only half the quota of first preference votes. Thus, in a six-seat district the effective threshold would be 7.14% of first preference votes (100/(6+1)/2). The need to attract second preferences tends to promote consensus and disadvantage extremes.

Party magnitude
Party magnitude is the number of candidates elected from one party in one district. As party magnitude increases a more balanced ticket will be more successful encouraging parties to nominate women and minority candidates for election.

But under STV, nominating too many candidates can be counter-productive, splitting the first-preference votes and allowing the candidates to be eliminated before receiving transferred votes from other parties. An example of this was identified in a ward in the 2007 Scottish local elections where Labour, putting up three candidates, won only one seat while they might have won two had one of their voters' preferred candidates not stood. The same effect may have contributed to the collapse of Fianna Fáil in the 2011 Irish general election.

Elected President or Prime- Minister
A president is always elected as a winner (winner-takes-all), and as such a president may exist above a parliament that was voted in according to a different election format. This situation is found particularly in South America. In the case of Brazil, for instance, an empowered President is elected while the House was elected proportionally. The strong position of the single President is countered by a much divided House and this may result in a weakening of the benefits associated with proportional representation. Compare this situation to the United States, where the strong President is countered by just two parties that can be considered both by themselves as also strong. As such, the strong power of the President can be countered by the strong support/opposition of the parties. With a proportionally elected House, a President may strong-arm certain political issues.
A Prime-Minister is never elected, but is a 'derivative' of the general election. In most cases, the power of the government is not split among different sections of the government (of President, Senate and House) and power is found with just the House. A Prime-Minister can be seen more as a manager than as a straight-out leader. Nations with district elections (such as the UK) and nations with proportionally elected representatives (such as Spain) can have a Prime-Minister.

Other aspects of PR can influence proportionality such as the size of the elected body, the choice of open or closed lists, ballot design, and vote counting methods.