The Senate count is more complicated than a count for the House of Representatives. Counting of first preferences begins on election night but the full count cannot be completed until several weeks after the election.
To be elected to the Senate, a candidate needs to gain a quota of the formal votes. The quota is calculated by dividing the total number of formal ballot papers by one more than the number of Senators to be elected and then adding '1' to the result (ignoring any remainder). This is how the quota for South Australia (SA) was calculated at the 2010 Senate election:
|1 009 578||
+ 1 = 144 226*
|(6 + 1)|
Therefore the quota, or number of votes required to be elected, in SA at the 2010 federal election was 144 226.
*Note: When determining the quota, any remainder is disregarded.
The first preference votes for the Senate are counted in the same manner as for the House of Representatives. The ballot papers are sorted according to which candidate has received the number '1' preference on each ballot paper. Candidates who receive the quota, or more, of these first preference votes, are elected immediately.
As a general rule, when a candidate is elected with a surplus of votes, that surplus is transferred before any exclusions are undertaken.
Any surplus votes the elected candidates receive (i.e. votes in excess of the quota they needed), are transferred to the candidates who were the second choice of voters. Because it is not possible to determine which votes actually elected the candidate and which votes are surplus, all the elected candidate's ballot papers are transferred at a reduced rate.
Candidate A gains 1 000 000 votes. If the required quota was 500 000 the surplus would be 500 000.
The transfer value therefore would be:
|1 000 000|
Candidate A's ballot papers (1 000 000) are then re-examined in order to determine the number of votes for second choice candidates.
If Candidate A's ballot papers gave 900 000 second preferences to Candidate B they would receive 900 000 X 0.5 = 450 000 votes which are added to the votes they received in the first count.
If Candidate B is then over the quota, they are elected and their surplus votes transferred in the same way.
As a result of this process of transferring surplus votes, other candidates may be elected. If all surplus votes from elected candidates are transferred and there are still some unfilled positions, further counting is undertaken as explained below.
Starting with the candidate who has the lowest number of votes, unelected candidates are excluded from the count. Their ballot papers are distributed to the remaining candidates to whom the voters have given their preferences. If any of the remaining candidates obtain a quota through this process of distribution, they are declared elected. Their surplus (if any) is transferred before any other candidates are excluded. The above process continue until all Senate positions are filled.
Counting for the Senate takes longer than the House of Representatives because of the complex nature of the counting system used. It is some weeks before all Senators are declared elected.
The declaration of the poll for the Senate is made by the Australian Electoral Officer for that state or territory.