The claim

"Anthony Albanese should do what I had to do at the last election and win a seat in his own right without having to rely on Liberal preferences," federal Greens MP Adam Bandt said in a media release.

In response to claims from Mr Albanese of a secret preference deal between the Greens and the Liberal Party involving key House of Representatives seats in the upcoming federal election, Mr Bandt accused Labor's infrastructure and transport spokesman of "begging" the Liberals for preferences.

"It speaks volumes about the modern Labor Party that they are reliant on the Liberals to keep their seats in Parliament," Mr Bandt said.

Did the Greens retain the seat of Melbourne in their own right without having to rely on Liberal preferences at the 2013 election as Mr Bandt suggests? ABC Fact Check investigates.

The verdict

Mr Bandt's claim is overstated.

Mr Bandt did not receive enough first preference votes at the 2013 election to be elected "in his own right" without preferences, and he relied on minor party, independent and Liberal Party preferences to be elected.

While the Liberal Party how to vote card preferenced Mr Bandt last, a third of Liberal voters disregarded this and preferenced Mr Bandt ahead of the Labor candidate.

There were 53 electorates, or roughly one-third of all electorates, at the 2013 election in which the candidate won on the primary vote alone, meaning that roughly two-thirds of seats were decided on preferences, as Mr Bandt's was.

But experts say that the proportion of preferences that Mr Bandt relied on was small relative to his primary vote and that he was the clear winner of the seat.

By contrast, there were 15 seats, or 10 per cent of electorates, which returned results which elected a different candidate to the primary vote winner, such as the rural Victorian seat of Indi.

Voting in the House of Representatives

Members of Australia's federal lower house, the House of Representatives, represent 150 areas known as electoral divisions.

Each member is elected by voters who reside in the area in a preferential system, as opposed to a first past the post system, under which candidates with the most votes are elected and preferences are not considered.

Under the preferential system in the lower house, voters are instructed to place a '1' in the box next to the candidate who is their first choice, then a '2' for their next choice, continuing until all boxes on the paper are numbered.

All boxes are required to be numbered for the vote to be considered formal.

After voting closes, the number of first preferences, or primary votes, are counted for each candidate in each electorate.

A candidate with more than 50 per cent of the primary votes is declared elected.

If no candidate has more than 50 per cent, the candidate with the fewest amount of primary votes is eliminated after this count, and each of that candidate's votes is distributed to the candidate who was marked as second preference on each ballot paper.

After these votes have been allocated to the remaining candidates, if there is still no candidate with over 50 per cent of the vote, the candidate with the fewest votes is eliminated once again, and his or her preferences are distributed.

This process continues until there is a candidate with over 50 per cent of the vote, who is then declared elected.

"The point of the system is to elect the most preferred candidate, to choose the candidate that can build an absolute majority of support in the electorate rather than the simple majority required under first past the post voting," ABC elections analyst Antony Green said in a blog post in 2010.

At the 2013 election, 53 lower house seats were decided on first preferences only.

The remaining 97 seats, including Mr Bandt's seat of Melbourne, were decided on preferences.

Mr Albanese's seat of Grayndler was also decided on preferences — his primary vote was high at 47.2 per cent, but a re-distribution has made his election in 2016 less certain.

How the count unfolded in Melbourne in 2013

In 2013, the ballot for the seat of Melbourne attracted 16 candidates.

Mr Bandt received 36,035 primary votes, or 42.62 per cent of the 84,551 formal votes in the count.

Throughout the count, Mr Bandt picks up 2,839 preference votes from minor party and independent candidates, bringing his total to 38,874, or 45.98 per cent, at the second to last count.

At this count, there are three candidates left in the ballot: Mr Bandt, Liberal candidate Sean Armistead, and Labor candidate Cath Bowtell.

Mr Armistead has the lowest proportion of the preferred vote at this count with 25.42 per cent, so he is excluded, and the 21,494 preferences on his ballot papers are distributed to the two remaining candidates.

It is these remaining preferences that bring Mr Bandt's count to 46,732, or 55.27 per cent, which sees him pushed over the 50 per cent threshold and elected.

Preferential treatment

In 2013, Mr Bandt's primary vote in the seat of Melbourne was 42.62 per cent, followed by Labor candidate Cath Bowtell.

The Liberal candidate, Sean Armistead, handed out 'how-to-vote' cards putting Mr Bandt last.

Mr Green told Fact Check that Mr Bandt's high first preference vote was the main reason he got elected.

"He led on first preferences, which means it required Liberal preferences to defeat him. Liberal preferences to Labor were required to flow very strongly to defeat him, so even though the preferences were against him he still won, because he led on first preferences and he led by far enough," he said.

Kevin Bonham, a psephologist from the University of Tasmania said that Mr Bandt's primary vote was "high enough that the proportion of Liberal preferences he needed to get over the line was very small."

A Liberal Party how to vote card for candidate Sean Armistead in the seat of Melbourne shows the Liberals preferenced Adam Bandt last at the 2013 election in the seat. ( ElectionLeaflets.org.au )

Dr Bonham told Fact Check that if every Liberal voter had followed the how to vote card, Mr Bandt would have been defeated.

"What he's saying is true in the sense that he won despite the Liberals preferencing against him on their how to vote card, but he still did rely on some votes from Liberal party voters going his way anyway."

Mr Green told Fact Check that an informative comparison to make with Mr Bandt's seat at the 2013 election would be the rural Victorian seat of Indi, where the incumbent Liberal member Sophie Mirabella was defeated by independent Cathy McGowan, whose primary vote was lower.

"... Sophie Mirabella was on 44.7, now she was run down by strong flows of preferences, massive flows of preferences. Now Bandt got 42.6 and he won easily, and the reason he won easily is that the preference flows weren't strong against him ... that comparison with Indi is informative, because if he's saying that he won in his own right, then how does that explain Sophie Mirabella?" he said.

"He wasn't elected in his own right as a political scientist would say, because elected in his own right would normally be 50 per cent of the first preference vote, but he didn't rely on preferences to win."

He told Fact Check that at the 2013 election, preferences changed the result of the seat in only 10 per cent of electorates, meaning that "the result after preferences is different than the first preference winner".

Sources

Editor's note (12/05/2016): This fact check originally stated that Anthony Albanese was elected on primary vote alone in 2013, which was incorrect. It has been changed to reflect Mr Albanese's primary vote of 47.2 per cent and his election by preferences. It does not change our verdict.