voting systems explained
"First past the post" is the colloquial name for the way we elect our MPs in the UK, and local councillors in England and Wales. The candidate who gets most votes in each constituency wins, even if their vote falls far short of a majority. FPTP is used in very few countries, almost all with a British colonial legacy; these include the USA (with an electoral college), Canada and India.
Several countries have rejected FPTP: New Zealand introduced a Mixed Member System in 1996, and South Africa moved to a proportional list system at the end of the Apartheid era. Justin Trudeau was elected as Canadian Prime Minister in 2015 on a pledge to ditch FPTP, though this reform has not yet taken place.
Advantages of FPTP include the fact that it is simple, and embodies a "consituency link", where people are represented by a local MP. However, the allocation of parliamentary seats under FPTP bears no mathematical relationship to the votes cast in an election, and it sometimes leads to very anomalous outcomes. In 1951, the Conservative Party won an overall majority in Parliament despite getting fewer votes than the Labour Party! In 1974, Labour became the biggest party in Parliament, despite getting fewer votes than the Conservatives.
The Second Ballot system works similarly to FPTP, with single-member constituencies. However, if no candidate wins more than 50 per cent in the first round, a run-off is held one or two weeks later between the top two candidates in the first round.
This system is used for presidential elections in several countries (notably in France); it is also used in France for all elections which return a single member.
The SB system is no more proportional than FPTP, and can give rise to problems with tactical voting; it is also expensive to run and can cause "voter fatigue". While SB it is not a bad system for electing a single candidate (eg for presidential elections), the lack of proportionality means it is not the most suitable system for parliamentary elections.
SV Is a hybrid system similar to SB, except that people vote for their first and second choices on the same day. The first choices are counted, the top two candidates remain in the race, and the second preferences of people who voted for eliminated candidates are then added in. Following the recommendations of the Plant Commission, this system was adopted in the UK for elected mayors and police and crime commissioners.
The aim of the system is to maximise the support for the winning candidate. However, with more than three candidates in the field, voters face the problem that they don't know for sure who the two candidates in the run-off round will be. Voters who cast both their first and second votes for candidates who are eliminated after the first round will effectively have no vote at all. As with the Second Ballot system, SV is not a bad voting system for electing a single candidate. However, for parliamentary elections it is not a proportional system.
Like FPTP, this system is based on single-member constituencies; but instead of voting for a single candidate with an ‘X’, voters rank candidates in order of preference, 1, 2, 3 … . If no candidate has more than 50 per cent of the votes, the candidate with fewest votes is eliminated and their votes are redistributed among the other candidates according to voters’ second preferences. The process continues until one candidate achieves a majority (50 per cent of the vote plus 1).
This system is used in Australia in elections for the Lower House, and for the selection of the leader of the Labour Party. AV was the alternative to PR offered in the 2011 AV referendum on voting systems. While an AV system removes the need for tactical voting, there are many other problems - it is not a proportional system, and could in fact lead to results that are less proportional than FPTP.
Many variants of AMS are possible. All involve two "layers" of MP - the first being elected to represent a constituency, in the same way as FPTP, and the second elected on a regional basis. Constituency MPs are nominated by their local parties, as under FPTP, and regional MPs come from ranked lists submitted by regional parties. Voters typically have two votes – the first to vote for a constituency MP, and the second to vote for their party of choice.
The constituency votes are counted first; regional seats are awarded as ‘additional’ or ‘top-up’ seats to to compensate for the disproportionality of the FPTP election.
AMS systems are very flexible. In New Zealand and Germany, half the seats are awarded on a regional basis, which produces a very proportional system. By contrast, the Plant Commission proposed a much more minimal version of AMS for the UK, with less than 1/4 of the seats awarded on a regional basis; this would be much less proportional, although still better than FPTP. Additionally, it is possible to impose a threshold, so that parties need to win a certain percentage of the popular vote, or at least one constituency, in order to get any regional seats.
AMS is used for the Scottish Parliament, the Assembly for Wales and the London Assembly. It is also used in New Zealand (where it is known as Mixed Member Proportional (MMP), in Germany (where it was imposed by the Allies after then end of WWII), and in a number of other countries. A form of AMS was supported by members of the Plant Commission (MMS), the Jenkins Commission (AV+), and the Hansard Society, the Institute for Public Policy Research and the New Zealand Constitutional Convention.
AMS systems are sometimes known as MMS. In 1993, the Plant Commission proposed the introduction of a "mixed member" system, a minimalist version of AMS specifically designed to overcome most of the objections to electoral reform voiced by Labour FPTP supporters. This proposal involved 500 single-member constituencies and 150 additional regional members; to gain additional members a party would have to win one constituency.
This system was devised by the Jenkins Commission (a commission set up by the Labour Government in 1997 to report on voting systems). It was the Jenkins Commission's recommended choice for Parliamentary elections, but has never been used anywhere in the world.
AV+ combines elements of the Alternative Vote (AV) and the Additional Member System (AMS); AV would be used instead of FPTP in the constituency contests, and the party lists would be ‘semi-open’, giving voters additional choice. The Jenkins report recommended that 80-85% of parliamentary seats should be elected by AV, with the remainder elected from party lists. The system has been criticised on the grounds that this would not provide a sufficient degree of proportionality.
Under list systems, political parties produce ranked lists of nominated candidates. This may be done at national or regional level. Voting takes place in one of two ways.
Under a CLOSED LIST system, voters simply cast their vote for a party. A formula (in European elections, the D’Hondt method) is used to convert parties’ shares of the votes into seats. If a party wins, say, three seats, then the top three candidates on its list are elected.
Under an OPEN LIST system, the parties still publish ranked lists of candidates, but voters are able to vote for the candidates they prefer, rather than simply voting for their party of choice. Under an open list system, if a party has enough support to win three seats, it is the three candidates of that party with most personal votes who are elected.
List systems of different kinds are used in most European countries. Since 1999, we have elected our MEPs using a closed list system. List systems come the closest of any electoral system to full proportionality. However, there is no constituency link under lists systems - all MPs represent a large region. Thus, a list system may not be the most popular choice for replacing FPTP in the UK.
STV is a voting system based on multi-member constituencies. In Ireland, which uses STV, constituencies each have between 3 and 5 MPs. Each party nominates a list of candidates, and voters rank the candidates in order of preference - it is possible for voters to "mix and match" candidates from different parties.
At the count, candidates who reach the necessary "quota" (the number of voters divided by the number of seats, plus 1) are automatically elected; otherwise (as in AV) the lowest-scoring candidate is eliminated and their votes transferred to other candidates according to second and subsequent preferences. This process continues until all the seats have been allocated.
An additional feature of STV is that votes are also transferred from candidates with more votes than they need to secure election, according to second and subsequent preferences of the people who voted for the winning candidate. Thus, STV does very well at minimizing "wasted" votes, both votes cast for losing candidates and surplus votes cast for candidates who win easily. However, as STV is generally used in smaller electoral districts it does not always guarantee the same proportionality as systems which use larger districts, and in a democracy where many political parties are active, smaller parties may be at a disadvantage similar to their experience under FPTP.
STV is used in the Republic of Ireland, Northern Ireland (except for Westminster elections), Malta and for the Senate elections in Australia. It has been used for Scottish local elections from 2007, and was recommended by the Sutherland Commission for local elections in Wales.