Published by Australian Academy of Science
Can we count on your vote? Box 1 | Counting the Senate vote

Counting for the Senate starts with the allocation of all first preference votes. A candidate who reaches the quota after this stage is elected. For example, let’s say Emiko, Gerard, Harry, and Ingrid are candidates for two Senate seats in the Australian Capital Territory, where there are 200,987 voters and the quota for a seat is 66,996 votes.

The first preference votes are:

Emiko Gerard Harry Ingrid

83,498 54,781 44,471 18,237

Emiko has reached the quota and is elected. She received 16,502 votes above (or surplus to) the quota of 66,996. Her surplus votes are now worked out as a proportion of her total vote:

• 16,502 divided by 83,498 = 0.19763347 (8 decimal places, no rounding).

Emiko's 83,498 votes are then given to their second preference, after being multiplied by 0.19763347:

• 55,009 of Emiko's second preferences go to Ingrid, so Ingrid gets
  55,009 x 0.19763347 = 10,872 extra votes.

• Harry gets 24,977 preferences: 24,977 x 0.19763347 = 4,936 votes.

• Gerard gets 3,512 preferences: 3,512 x 0.19763347 = 694 votes.

So now we have:

Gerard Harry Ingrid

54,781 44,471 18,237

+ + +

694 4,936 10,872

= = =

55,475 49,407 29,109

You can see that the number of preferences allocated is exactly Emiko's surplus:
694 + 4,936 +10,872 = 16,502.

None of the three has reached the quota of 66,996 votes. And even though Ingrid received most of Emiko's surplus, she still gets excluded because she has the least number of votes.

Ingrid's 18,237 first preference votes are now distributed as follows:

• Votes with Gerard or Harry as second preference go straight to them.
• Votes with Emiko as second preference go to their third preference, which must be either Gerard or Harry.

The situation now is:

Gerard Harry

54,781 44,471

+ +

1,223 17,014

= =

56,004 61,485

These totals don’t include Emiko's 16,502 surplus votes, which have to be redistributed again. They are distributed between Gerard and Harry, since Ingrid is no longer a candidate. This is done by multiplying Emiko's first preference votes (83,498) by the same proportion as before (0.19763347) and allocating them as follows:

• 20,391 of Emiko's first preference votes go to Gerard, so he gets
  20,391 x 0.19763347 = 4,030 extra votes.
• 63,107 of Emiko's first preference votes go to Harry, so he gets
  63,107 x 0.19763347 = 12,472 extra votes.

The final picture is:

Gerard Harry

54,781 44,471

+ +

1,223 17,014

+ +

4,030 12,472

= =

60,034 73,957

Harry reaches the quota and is elected to the second seat.

Related site

• Australian Electoral Commission
  • Voting: The Senate
  • Voting: House of Representatives