How do you correctly number a ballot paper in a House of Representatives election?

On a House of Representatives ballot paper, you correctly number every box from 1 to the number of candidates, with 1 indicating your most preferred candidate, 2 your second preference, and so on through to the last candidate. The ballot is informal (does not count) if you leave any box blank, write non-numbers, or repeat or skip numbers.

Federal House ballots use full preferential voting, requiring every box to be numbered. If there are seven candidates, you must number from 1 to 7. If there are nine, you must number from 1 to 9. The Australian Electoral Commission provides a polling-place worker who can answer questions about how to vote without commenting on candidates or parties. Sample ballots and how-to-vote instructions in the AEC's official Voting in the Federal Election guide are sent to all enrolled voters before the election.

The Senate ballot is different. The Senate uses single transferable vote with two options: vote 'above the line' by numbering at least six party boxes in order of preference, or vote 'below the line' by numbering at least 12 individual candidate boxes in order of preference. Voters who want their preferences strictly applied vote below the line for full control. The 2016 reforms abolished group voting tickets that previously allowed parties to direct above-the-line preferences.

Several other rules apply. Voters can use a tick or a cross as the number 1 (and the ballot is still counted), but other numbers must be in proper form. Writing names, messages, or symbols on the ballot makes it informal. Tearing or marking the ballot in unusual ways may make it informal. About 5 to 6 per cent of House votes are informal at federal elections, often because voters number only their first preference, leave boxes blank, or skip numbers. The AEC actively educates voters before each election about how to vote formally, with particular outreach to communities where English is a second language.