M=1 is the endpoint of the continuum of M

The BBC reports that there is a debate in Jersey about a possible change in the island’s electoral system. “Deputy Montfort Tadier wants to introduce a mixture of single transferable and alternative vote systems.”

Of course, that actually would be the same system, but a mixture of district magnitudes. Single transferable vote (STV) simply reduces to alternative vote (AV) when moving from any magnitude greater than one to a single-seat district.

The article further notes that “Jersey currently has a mix of single and multi-member constituencies” and that “Jersey currently uses the first-past-the-post system, for all elections.”

It is interesting that when the rule for determining winners is plurality (first past the post), it is considered the same system, independent of magnitude. Yet when referring to a rule of transferable votes, applications to M=1 (single-seat district) and M>1 (multiseat district) are considered different “systems”.

Further, the article attempts to clarify: “The single-transferable-vote means a vote could be transferred to a second preference if the first does not succeed.” Yes, and so does the alternative vote, which is defined next as being “where candidates are ranked in order of preference.” Yes, and so is the single transferable vote.

5 thoughts on “M=1 is the endpoint of the continuum of M

  1. As we’ve seen before, the (relatively) uninitiated will have trouble with the terminology, especially the media… In their defence, there’s obviously a far more substantial difference between AV and STV than between FPTP and MNTV.

    I personally think it’s confusing to refer to anything other than single-member plurality as ‘First-past-the-post’, but it is not uncommon.

  2. Small external territories often have slightly odd electoral arrangements. The legislative assembly of Norfolk Island (pop 2800, area 34.6 k sq, distance to Sydney 1626 k) is elected by cumulate vote with M=9. Since electoral designers just adore not only reinventing, but renaming, the wheel the system is known as weighted first past the post.

    The islanders are partially descended from the Bounty mutineers who were resettled there when Pitcairn Island was discovered by the Royal Navy. The island also has an administrator to represent the Queen, a chief minister responsible to the assembly, its own language (a mix of Tahitian and 18th century English), an interesting conspiracy theory that Australia stole it from Queen Victoria, a gigantic public debt, and an independence movement.

  3. I agree with JD that it is odd to lump M>1 plurality systems under the category of FPTP. Unless, that is, the system is first list of candidates wins all (as in the US electoral college). So we have an unnecessary distinction being made between ranked-choice transferable vote systems, according to M, and a confusing conflation of plurality methods in M=1 and M>1. All in one short BBC article!

    On what Norfolk Island has to offer, Alan forgot the famous pines. Which, of course, aren’t actually pines any more than cumulative vote is a type of FPTP.

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