Preferential voting

Preferential voting is a system of voting in which a voter ranks all candidates from first to last. It is used in some countries to various extents, most widely in Australia, where it is used in local, state, and federal elections.

Australia

In Australia this form of voting has been in place for a long time and has given some benefit to small parties such as the Democrats, The Greens and One Nation who would find it financially difficult to run a campaign in a country which uses first past the post systems such as the US and the UK. A result in an Australian electorate could look something like this:

White(One Nation)	6,000	06.0%
Wilson (Labor)	45,000	45.0%
Jones (Liberal)	35,000	35.0%
Taylor (Green)	10,000	10.0%
Walker (Ind)	4,000	04.0%

As in most cases a single candidate will not receive more than 50% of the votes (unless the seat is very secure) that is needed to win that electorate so then after the first preference votes (or primary votes) are counted the person with the lowest amount of votes, which in this case is Walker who is an independent will have their votes given among the people that were number 2 on that persons preference list.

White(One Nation)	6,000	06.0%
Wilson(Labor)	45,000	45.0%
Jones (Liberal)	39,000	39.0%
Taylor (Green)	10,000	10.0%

Walkers' 4000 votes were all given to Jones the Liberal Candidate (Note that this is a heavily simplified version of the Australian preferences system as most of the time votes will go to every other candidate on the list and not just to 1 candidate) giving him 39% of the total vote.

Wilson (Labor)	51,000	45.0%
Jones (Liberal)	39,000	45.0%
Taylor (Green)	10,000	10.0%

White from the One Nation political party is next to have their preferences tallied up as they have the next lowest amount of primary votes at 6%. In this case all of his second preference votes go to the Liberal party meaning that they now has 45% of the total vote. In this case the Greens second preference has to be counted to give a 2 party preferred result. Even if a party has won by this stage the third parties' preferences have to be counted to give a 2pp result.

Wilson (Labor)	54,000	52.0%
Jones (Liberal)	46,000	48.0%

The 2 party preferred result is now obtained from the Greens second preference votes and 7,000 votes were given to the ALP giving them a final percentage of 52% which gives them a tight victory and the 3,000 green votes that were given to the Liberal Party mean that they have 48% of the 2pp result. Voting is now complete and no more has to be done unless the result were really close and therefore a second check will be needed to confirm the results.

Advantages

Advantages of this system include:

• Removing the spoiler effect. When two ideologically similar candidates run for the same public office under a first past the post system, they steal votes from each other, allowing a less supported candidate to win.

• It makes it possible for voters to support minor parties and independents as they know that their preferences may be used to decide the winner. This is important as votes for minor parties and independents are not wasted.

• It means that parties who have similar philosophies or policies can give preferences to one another in order to help each other win.

• It gives a strong two-party system which ensures solidity in the parliamentary process.

Disadvantages

Some disadvantages of this system include:

• It is very complicated compared to first past the post.

• It produces a higher level of informal votes especially with Australia's compulsory voting. In the Australian system of preferential voting, if each candidate is not numbered, or a number is skipped, the ballot can be thrown out. With some electorates having twenty candidates running, voters can easily make mistakes and have their vote excluded.

• The two-party system can be a detriment to minor parties and independents who want to hold office.

• Voters could be forced to give preferences for candidates they might not wish to support in any way although voters for two major parties don't need to worry as they will rarely or if ever need to be counted as they will most likely already have the most primary votes.

Further reading

http://www.australianpolitics.com/elections/features/preferential.shtml