The AEC has finally released its report on informal voting. You can view the full report here.

Here are some of the key findings:

Of the informal vote, 21% consisted of blank ballots, 33% of ‘1’ only
votes, 9% ticks and crosses, 3% ‘Langer’ votes, 15% non-sequential
numberings, 14% marks and scribbles, with 5% off in other.

The category to increase in 2004 was marks and scribbles, up from 6% to
14%, corresponding to most of the small increase in informal voting
between 2001 and 2004. However, the rise between 1990 and 2004 is
mainly due to numbering problems.

Of the ‘1’ votes, the highest rates were 36% in the ACT and NSW, and
45% in Queensland, the three jurisdictions where a ‘1’ only vote is
valid at local elections. The lowest was 22% in Victoria. Victoria does
not currently have an upper house with a ‘1’ vote only option, perhaps
the reason Victorian voters are less likely to use that option.

The report also found a strong causal relationship between informal
voting and the number of candidates contesting. That relationship was
even stronger if you only looked at the informal categories of
incomplete and non-sequential numberings. In other words, the more
candidates there are, the higher the informal rate.

In Greenway with 14 candidates, the non-sequential category reached
28%, the ‘1’ only votes 27%. The overall informal vote reached 20.5% at
Marsden Park.

Across the country, half of the informal vote consisted of ‘1’ only
votes or incorrectly numbered ballots. That proportion reach 60% if you
also include ticks and crosses. All of these votes would be formal for
the current Senate voting system.

And with a NSW and Queensland state election due in the 12 months
before the next federal election, the rate of ‘1’ only and incomplete
numbered ballots in those two states may rise at the next Federal
election without corrective action.

One solution. Halve the informal vote by introducing optional
preferential voting. Given it is Labor that benefits from preferences
at Federal elections, sounds like a win on principle, win on politics
option for the Liberal Party.