Filling all the BTL Squares – Incidence at the 2019 SA Senate Election

As promised, here’s one of my occasional Graph of the Day posts on something I’m currently researching.

How many people voting below-the-line (BTL) on Senate ballot papers go on to fill in all the squares? Here’s the answer in a graph using South Australian Senate data from the 2019 Federal election.

If you hover over any point on the graph you can find the total number of ballot papers with a given number of formal BTL preferences. There were a total of 42 candidates on the ballot paper.

Be warned, the graph uses a logarithm scale on the left hand axis to show the number of ballot papers. If I used a simple total as the left axis, the only points that would appear would be at 6, 12 and 42 preferences.

And apologies, as with all graphs, it is better viewed on a computer than a mobile phone.

  • A total of 82,813 votes were counted as below the line votes, 7.6% of all South Australian Senate ballot papers.
  • The ballot paper instructions state to fill in a minimum 12 preferences, and 61.9% of all below-the-line votes counted for only 12 preferences.
  • The savings provision for Senate BTL votes is that at least the first 6 preferences be formal. 4,095 ballot papers were saved by this provision, representing 4.9% of all BTL votes or 0.4% of all votes.
  • 13.3% of BTL votes had between 13 and 18 preferences, 5.0% between 19 and 41.
  • Only 12,333 voters successfully filled in all 42 squares, 14.9% of all below-the-line votes or 1.1% of all formal votes.
  • As a percentage of each party’s total vote, both ATL and BTL, the percentage with 42 BTL preferences ranged from 0.6% for the Liberal Party, 0.8% Labor and 0.8% One Nation, up to 2.9% for the Greens, 3.0% Fraser Anning’s Conservative National Party, 3.1% Australian Democrats, 3.4% Centre Alliance and 3.9% Australian Conservatives.
  • The number of voters filling in all BTL preferences declined as the number of candidates increased. 14.9% of BTL voters filled in all squares in South Australia where there were 42 candidates, compared to 1.1% of BTL votes in NSW where there were 105 candidates.

I published statistics on the length of ATL and BTL preferences across states at the 2019 Senate election in this post I published in January 2020.