AV Referendum: do only three countries use AV?

"It's a system so obscure that it is only used by three countries in the whole world - Australia, Fiji and Papua New Guinea."
David Cameron, 11 April 2011

The claim that only three countries worldwide use the AV electoral system that is the subject of May's referendum has been given a wide airing by those opposed to dropping the current First-Past-The-Post (FPTP) system.

David Cameron used it when speaking to party activists at the launch of the Conservative campaign ahead of next month's ballots, echoing the No2AV assertion that the proposed system is so complex that "it is used by just three countries in the world."

But today's Independent labels this claim a "myth", and argues that we can add at least one more Western democracy to this list: Ireland. The paper writes that: "[AV] is also used to choose the Irish President, in many US mayoral elections and for the Best Picture at the Oscars."

Leaving aside the Academy Awards and the US mayoral elections (which, like the London mayoral ballot, cannot be considered nationwide polls), the example of Ireland is intriguing.

A glance at the Irish Government's own guide to its election system might suggest that the Independent has erred: "The President is elected by the direct vote of the people. Voting is by secret ballot on the Single Transferable Vote system."

However this is not necessarily so. The Single Transferable Vote (STV) system is indeed used by Ireland for most of its parliamentary elections. Like AV, the system asks voters to list the candidates on the ballot paper in order of their preference. However unlike AV, STV makes use of multiple member constituencies (in which more than one candidate can be elected, as in many UK council wards), meaning that surplus votes can be reallocated from elected candidates as well as those eliminated.

However these differences do not come into play in elections where only one position is up for grabs, such as the Irish presidency, or indeed parliamentary by-elections for single seats. Whilst these may nominally keep the STV tag given by the Irish Government, they do in effect operate as AV ballots.