Fact sheet - Hare Clark
What is the Hare-Clark electoral system?
In the ACT, members of the Legislative Assembly are chosen through a proportional representation system called the Hare-Clark system. This system is a type of proportional representation known as the single transferable vote method.
Voters indicate their preferences for individual candidates. To be assured of winning a seat, a candidate must secure a quota of votes. Each voter has one vote, which can be transferred between candidates according to their preferences until all seats are filled.
In the ACT, the Hare-Clark system is used to elect 25 members across 5 multi-member electorates. These electorates—Brindabella, Ginninderra, Kurrajong, Murrumbidgee, and Yerrabi—each elect 5 members.
How did the Hare-Clark electoral system get its name?
The system is named after Sir Thomas Hare, an English lawyer who developed a proportional representation system in 1859, and Andrew Inglis Clark, a Tasmanian Attorney General who adapted Hare's system for use in Tasmania. It was first implemented in Tasmania in 1897 and is still used there today to elect the Tasmanian House of Assembly.
The Hare-Clark electoral system in brief
Step 1
Count the first preference votes for each candidate.
Step 2
Calculate the quota:
total number of valid votes
------------------------------------- +1
number of vacancies +1
Step 3
Any candidate with votes equal to or greater than the quota is declared elected.
- If all vacancies have been filled, the election is completed.
- If all vacancies have not been filled, does any candidate have more votes than the quota?
- If yes then go to step 4.
- If no then go to step 5.
Step 4
Distribute the successful candidate's surplus votes to continuing candidates according to the further preferences shown on the ballot papers by those voters. (A 'continuing candidate' is one neither elected nor excluded.) Calculate each continuing candidate's new total votes, then go back to step 3.
Step 5
If there are more continuing candidates than there are vacancies remaining unfilled, exclude the candidate with the fewest votes and distribute this candidate's votes to continuing candidates according to the further preferences shown by those voters. Calculate each continuing candidate's new total votes then go back to step 3.
Or, if the number of continuing candidates is equal to the number of vacancies remaining, all of those candidates are declared elected and the election is completed.
Voting process
Voters rank candidates in order of preference using numbers 1, 2, 3, 4, 5 and so on. For 5 vacancies, voters are instructed to indicate at least 5 preferences. They can rank more candidates if they wish. If a voter doesn't mark the minimum number of preferences, the vote will be counted up to the point where preferences stop, as long as there's a first preference.
Getting elected
To be certain of securing a seat, a candidate must receive a quota of votes, calculated based on the number of valid votes and vacancies. A candidate might still be elected without a quota if the number of remaining candidates matches the number of unfilled seats.
The quota in a 5-member electorate will be one-sixth, plus one, or roughly 16.67%.
Ballot papers
Candidates' names are listed on the ballot papers in columns. Candidates nominated by registered political parties are listed in party columns, with the name of the party shown at the top of the column. Non-party candidates are included in one or more "ungrouped" columns on the ballot papers.
Where a registered party nominates only one party candidate in an election, that candidate is also included in an ungrouped column.
How votes are counted
Counting the first preferences
First, the number of first preference (or "1") votes for each candidate is counted. Ballot papers without a "1" or with multiple "1"s are informal and aren't included in the count. Ticks and crosses also cannot be counted.
After counting the first preferences, the quota is calculated, and any candidate meeting or exceeding the quota is elected.
Transferring surplus votes from elected candidates
If a candidate gets enough votes to meet or exceed the quota, they are elected. If they receive exactly the quota, all those votes are set aside and not counted further.
When a candidate has more votes than the quota, the extra votes are called the candidate's surplus.
These surplus votes are passed on to other candidates based on the next preferences marked by voters on their ballot papers. If a candidate has more first preference votes than the quota, all their ballot papers are distributed at a reduced value, known as a fractional transfer value. (see below). If a candidate has received more votes than the quota following a transfer of votes from another elected candidate or from an excluded candidate, only that "last parcel" of ballot papers that the candidate received are distributed to continuing candidates at a fractional transfer value.
After the surplus votes from an elected candidate are distributed, the total number of votes for each remaining candidate is recalculated. If any other candidate now has enough votes to meet or exceed the quota, they are elected. This process continues until all vacancies are filled, with surplus votes from newly elected candidates being distributed one by one.
How a fractional transfer value is calculated
The fractional transfer value is calculated using the following formula:
number of surplus votes
---------------------------------------------------------------------------------------
total number of ballot papers with further preferences shown
Excluded candidates
If seats remain unfilled after surplus votes are transferred, the candidate with the fewest votes is excluded. Their votes are redistributed to the remaining candidates according to voter preferences.
Ballot papers from candidates who are excluded are passed on at the value they were originally received. For example, ballot papers marked with a first preference have a value of "1," while papers received after surplus votes are transferred have a lower, fractional value. This value depends on how the surplus votes were transferred.
After distributing the papers from an excluded candidate, the total votes for each remaining candidate are recalculated. This helps determine if any candidate now has enough votes to meet or exceed the quota.
The process of transferring surplus votes from elected candidates and excluding the candidate with the fewest votes continues until all the positions are filled.
How are casual vacancies filled?
Under the Hare-Clark system, if a vacancy occurs in the Assembly, the process begins by recounting the ballot papers from the vacating member. This review identifies which candidate was the next most preferred among those who voted for the vacating member. Only candidates from the original election who express interest in the vacancy will be considered for this position.
If it is not possible to fill a casual vacancy using this method—perhaps because no candidates from the original election are available or willing—the Legislative Assembly will appoint a new member. If the vacating member was elected as a member of a registered political party, the new member must belong to that same party. If no party member is available or if the vacating member was an independent, the appointee cannot have been a member of a registered political party within the 12 months before the vacancy.