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Proportional representation explained

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Proportional representation (PR) is a type of vote counting system which can be used when there are multiple vacancies at an election. Under PR systems, candidates are elected on the proportion of the total vote that they receive. They must achieve a predetermined quota.  Preferences are transferred from elected or excluded candidates to continuing candidates in order to determine the most popular, or preferred, candidates. 

n 1987 legislation was passed by the Western Australian Parliament for the introduction of PR for Legislative Council elections in multi-member regions. In 2007, 20 years later, PR was also made law for multiple ward elections in local government authorities. At the same time the PR formula was modified to the Weighted Inclusive Gregory Method (WIGM) for both the Legislative Council and Local Government.

The PR vote counting system is designed to ensure that vacant positions (or seats) are allocated as nearly as possible in proportion to the votes received. The principle is simple but the steps in the process can be complicated. While the steps help ensure that the system is fair, it may take longer to finalise the result.

The following are the basic steps taken where the Weighted Inclusive Gregory Method (WIGM) is used in an election.



Informal ballot papers are set aside. First preference votes for each candidate on formal ballot papers are counted.



Calculate the Quota (Q)

Total Valid Votes

               ------------------------     +1 = Quota

No. of seats +1


     eg                        40 votes ÷ (3 seats + 1) = 10 + 1 = Quota of 11



Candidates with votes equal to or greater than the quota are elected. If all vacancies have been filled, the election is finished. If some vacancies remain unfilled, the votes of elected candidates are examined to determine if any received more votes than the quota (surplus votes).


If there are surplus votes to be distributed

If there are no surplus votes to be distributed.

The elected candidate’s surplus votes (those in excess of the quota) are distributed to candidates continuing in the count. They are distributed according to the next available preference marked on the ballot papers. All the elected candidate’s ballot papers are examined

and distributed at a transfer value (TV).


For ballot papers received from the elected candidate’s first preference votes, the current TV is


Number of surplus votes of elected candidate

Total votes of elected candidate


For ballot papers received from previous surplus distributions, the TV is


Current transfer value X  Previous transfer value

Total votes for each of the continuing candidates are calculated by multiplying the number of ballot papers to be transferred to a continuing candidate by the transfer value


Step 3 is then revisited.


The candidate with the least votes is excluded from the count.  That candidate’s votes are distributed to continuing candidates according to the next available preference indicated on the ballot papers.


The votes of an excluded candidate are distributed to continuing candidates at the same transfer value as they were received.


Each continuing candidate’s total votes are calculated, then:

·         Step 3 is revisited; or

·         If the number of continuing candidates is equal to the number of vacancies remaining unfilled, all those candidates are declared elected and the election is finished.

Note: A continuing candidate is one who has not yet been elected or excluded from the count.

For further information go to the WA Electoral Commission website



Acknowledgement of Country

The Government of Western Australia acknowledges the traditional custodians throughout Western Australia and their continuing connection to the land, waters and community. We pay our respects to all members of the Aboriginal communities and their cultures; and to Elders both past and present.