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PR-Squared and the 2015 General Election
PR-Squared is a new electoral system designed for the UK’s House of Commons. It typically elects a majority government; it elects one local MP from each constituency each of whom is dependent on the local vote; yet that still ensures that equal votes mean equal seats.
PR-Squared: a three-party system
Under PR-Squared there are ‘stable’ outcomes with three parties, probably not with four, and definitely not with five or more.
Various conundrums relating to electoral systems
Examples and counter-examples of non-intuitive behaviour in electoral systems,
with a new 12-voter example replacing the previous 55-voter case.
Apportionment, or How to Round Seat Numbers
It is desired to allocate a fixed number of seats proportional to some numbers (such as votes, population or even votes squared).
If each entity is to receive an integer number of seats, then the allocations must be rounded.
There are several ways to do this, with interesting and surprising properties.
PR-Squared: the Majoritarian Incentives of Voters and of Parties
PR-Squared gives strong majoritarian incentives to both voters and parties, but different incentives: voters to avoid tiny parties; and parties of size from small to just-sub-majority to form formal coalitions.
A Criticism Of The Jenkins Report
In late October 1998 The Rt Hon Lord Jenkins of Hillhead OM delivered to the Home Secretary The Report Of The Independent Commission On The Voting System.
The Commission’s terms of reference requested “an alternative to the present system”, with the obligation to “observe the requirement for broad proportionality, the need for stable government, an extension of voter choice and the maintenance of a link between MPs and geographical constituencies”.
This Report is deeply flawed, in part because the Commission was misled by the panel of academics constituted to advise it.
PR-Squared: UK, May 2010
Had PR-Squared been used in the UK’s May 2010 election, there would have been a fairer assignment of seats, but still no single party with a majority of seats.
PR-Squared in Israel: Bettering Israeli Politics
PR-Squared in the contest of the election to the Eighteenth Knesset held on 10th February 2009.
Superseded papers on PR-Squared: PR-Squared, the original description, PR-Squared: A New Description, a fully-worked example, some technical notes, PR-Squared in the context of New Zealand, and an updated table containing the results of the NZ 1999 election; PR-Squared: UK 2001 results, and voting power.
Examples of unusual voting systems
Including the election of the mayor of Cuckfield, and of honorary members of SEPTIC.
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There is a PR² group on Facebook. This was not created by, nor is it controlled nor endorsed by, the author, who is not a member of Facebook. Nonetheless, its existence might be of interest to some readers.
New essays on jdawiseman.com are announced on twitter. It is expected that tweets will be infrequent.