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Australian preferential voting system

The Australian preferential voting system is used in all 15 houses of parliament at federal and state Level, and in local government as well. It is essentially the same system that is known overseas as instant runoff voting.

Preferential voting is still fairly rare, which make Australia the place with the most experience in this area.

Table of contents
1 beginnings
2 why no run off ballots ?
3 risk of loss of power
4 one plus one equal three
5 spread of preferential voting
6 compulsary versus option preferences
7 two-party preferred vote
8 sample ballots
9 circumstances where preferential voting should be preferred
10 circumstances where preferential voting might be preferred
11 what voting system to select when selecting of a capital city
12 home team voting
13 compulsary voting
14 terminology
15 more than one vacancy
16 informal ballots
17 comparision of several voting systems
18 for schools


In the beginning, from before the times of secret ballots, the "first past the post" system was used. In those days, parties barely existed, and most candidates were elected as independents.

Australia was and is a sparsely populated country, as large as the continental United States. Voters often had to travel long distances to polling booths. The idea of having to travel twice to the polling booth, as would be required by runoff voting, was unacceptable.

why no run off ballots ?

Australia is a sparsely populated country, as large as the continental United States. Voters often have to travel long distances to the polling booths. The idea of having to travel TWICE to the polling booth, as might be required by Runoff Voting, beggars belief.

risk of loss of power

By 1910, parties had coalesed into a two-party system, Labour on the Left, and Non-Labor on the Right. Non-Labour is so-called because of numerous name changes.

In 1919, the establishment of a Rural Right Party threatened the governing Rightist Non-Labour Party, who promptly introduced Preferential Voting (IRV).

one plus one equal three

Once preferential voting was introduced, three cornered contests ceased to be a risk to either of the rightist parties, which have been in uneasy coalition ever since.

One leftist party plus one rightish coalition makes three parties, 1 + 1 = 3. Despite having three main party everyone still calls it a "two party system".

spread of preferential voting

Over the many decades since, IRV has spread to all 15 houses of parliament, and to others like it. Voters seem to generally like the system, and it certainly has the support of minor parties to show their flags on voting day.

IRV allows voting to vote for their true favourites, which risking some spoilage were the wrong Major party to win.

compulsary versus option preferences

Originally preferences in Australia were compulsary; you had to number every square. Some people do not like this and would rather have preferences optional. The Leftist Labour party also had a suspicion that it was disadvantaged by Compulsory preferencess because its supporters include frail and elderly people possibly not always able to write all the numbers.

Labour has managed to change to optional preferences in three houses of parliaments in two states.

two-party preferred vote

Preferent voting has developed some terminology to explain things clears, and because of wide usage in the media, especially on Election Night, the general public is quite familiar with these terms. The most important of these is "two party preferred".

The are now significant minor parties on both left and right which generally support the two Major Parties, including the Rightist Major Party which is actually a coalition.

Primary Vote is the votes that a Candidate actually receives in their own name. Two Party Preferred Vote is the votes that the winning and runnerup candidates receive after all preferences are distributed.

sample ballots

circumstances where preferential voting should be preferred

Preferential (IRV) voting allows the many rounds of a run off voting to be carried out in one transaction that takes say 10 minutes to fulfill. By comparison - as found out by the Utah Republican Party - multiple runnoff takes hours, by which time some delegates have dropped out because they are tired and have a job to go to the next morning.

circumstances where preferential voting might be preferred

If there are only two choices, then all voting systems "degenerate" to First Past The Post. FPTP can be done with black and white pebbles, which is beyond the capability of IRV. FPTP can also be done on the voices.

If there are more than two choices, then it may or may not be important that votes for third and minor parties are wasted (if the vote is important) or lost (if the vote is NOT important).

Only the other hand, FPTP would be sensible if you are in a great hurry and cannot spare the time for any Runoffs, Instant or otherwise, or when you do not have any paper to print the ballot papers on.

what voting system to select when selecting of a capital city

Elsewhere in this encyclopedia there is a item where selection of a Capital City for the state of Tennessee is used as an example to compare the merits of FPTP and IRV.

home team voting

Home team voting is a special problem that occasionally affects all voting system, whereby voter out of loyalty wish to vote for their home team first.

compulsary voting

In Australia, registering for the vote is compulsary, as is voting itself, on pain of a small fine. At elections, voters who do not wish to be fined for not voting can cast a informal vote.


Australian call this system "Preferential Voting" because their main focus is to rank all the boxes "[___]" in order of their preferences, 1, 2, 3, 4, 5, 6, 7, 8, 9. When these votes are counted, and a first preference for an unpopular candidate is excludes, it "runs off" to the next preference.

Americans are very familiar with Runoff elections, whether in a state house election Senators prior to 1910, and for runoff elections held a week or two later. Instant Runnoff Voting is clever choice of name by the CVD, that emphasise that Preferential Voting is really no different from Runnoff Voting.

more than one vacancy

Preferential Voting normally applies when there is one one vacancy to be filled. When there are two or more vacancies to be filled, the system can be call Single Transferable Voting.

But really, preferential voting is just a special case of STV. You might call them:

PV = PV1 = STV1 = 1 vacancy. PR = PVN = STVN = N vacancies.

Having such a muddle of names leads for fear, uncertainty and doubt, FUD.

Whereever possible this topic will choose names and abbreviations to improve clarity.

informal ballots

Informal ballots are ballot papers that are either blank or contain errors or ambiguities in the numbering of the "[___]" boxes. How does the choice of voting system affect the proportion of informal ballots.

comparision of several voting systems

The following voting systems seem near enough that they could be recorded on the same ballot paper.

PLUR Plurality voting - aka First Past the Post. RUN Runnoff voting - vote repeated a week later. MEET Meeting voting - all done in the same building. CUMM Cumulative voting APPR Approval voting IRVO Instant Runoff Voting - Optional Preferences. IRVC Instant Runoff Voting - Compulsary Voting.

See Comparison of voting systems.

for schools