Voters in the United Kingdom are set to go to the polls to decide if their first-past-the-post system for electing Members of Parliament (MPs) is to be exchanged with an alternative vote scheme. As it stands now, the candidate who receives the most votes in a district — a plurality, not a majority — wins the seat. The Alternative Vote — also known as an immediate runoff — allows voters to rank-order their several votes, thus requiring a majority to elect an MP.
The first-past-the-post system is quite easy to administer and even easier to count. Each voter casts a single vote. The candidate who receives the most votes wins the seat. The theoretical effects of this system are that it is easy for the voter to understand, it pressures the number of effective political parties downward, and it is unambiguous in how it is counted. The major drawback is that frequently the winner of the election did not receive a mandate from his or her constituents. The other effects of the first-past-the-post system can be seen as either strengths or weaknesses.
The Alternative Vote (AV) attempts to fix some of the perceived weaknesses without changing the perceived strengths. The AV requires that the winner of the district receives a majority of the votes cast in the district. To accomplish this, the voters have as many votes available to them as candidates running for the seat. The ballot contains a listing of all candidates for the seat. The voter merely ranks the candidates according to their desires.
In the counting of the ballots, the first round only counts the first-ranked candidates on the ballots. If a candidate receives a majority of the votes cast, then that candidate wins the seat and the counting is over. Should no candidate receive a majority, then the trickiness begins.
In the United Kingdom proposal, the candidate with the fewest votes is dropped from consideration and his or her ballots are distributed according to the second-ranked preferences on the ballots. If no candidate receives a majority with this second round, the candidate with the next-lowest number of votes is dropped and the votes owned by that candidate are distributed according to the next rank. In a very even district, this process may continue until there are just two candidates remaining. At this point, one of the candidates is guaranteed to receive a majority of the votes.
This electoral method is designed to ensure that the district winner receives a majority of the votes cast — defined in this new manner. The expected effects of this new system are to increase the number of effective parties standing for any seat — giving the voters a greater choice. An interesting corollary is that symbolic votes have almost no effect on the final election outcome; that is, if you decide to throw you first vote to a minor party, but rank a major candidate in second place, it will not hurt your major candidate (under real situations).
The Alternative vote is not very popular in the world. Only Australia, Fiji, and Papua-New Guinea use it:
Australia is the only major democracy to use the same type of AV system as the one being proposed for the UK, but voting is compulsory there. Papua New Guinea and Fiji also use AV - but most democracies use versions of proportional representation or first-past-the-post.
So, who is against Alternative Vote systems? In States with a well established two-party system, those two parties tend to be against AV systems, as they will lose their duopoly on power in the long run. Those who stand to win the most are the second-tier parties in two-party states. In the United Kingdom, the Conservatives are against the AV system; the Liberal Democrats are in favor; Labour is split. The nationalist parties — the Scottish National Party (SNP) and Plaid Cymru (PC) — in the UK also tend to be pushing for a "Yes" vote. In Northern Ireland, the majority party, Democratic Unionist Party (DUP), is against the AV, as is the Ulster Unionist Party (UUP) with its links to the Conservative Party. Those in favor of the AV include all minority parties: Social Democratic and Labour Party (SDLP), Sinn Fein, and the Alliance Party (connected to the Liberal Democrats).
So, what is the expected outcome? While I know of no polls that have been done in conjunction with this referendum, I highly doubt that it will pass in the United Kingdom. The vote is May 5. The results should be provided by May 6. Let us see.