Graphs of the Day – a few Charts on Preference Flows at the 2019 Election

This is a post I’d been playing around with and published by accident.

It was an experiment in finding new ways to graph two-party preferred and preference flows.

Seeing I’ve published the post, I should add a few comments.

Composition of Two-Party Preferred Vote

The graph and table below was an attempt to break down two=party preferred vote by the origin of the vote as first preferences.

In the graph and table below, I’ve pulled apart preference flows in the three-cornered contests, and also split the first preference support for all third parties into their destination preference. So 8.55% of the Green’s first preference vote ends up part of Labor’s two-party vote, and 1.85% part of the Coalition’s.

For all the talk of preferences deciding elections, in the end who wins depends more on whether Labor or the Coalition have the higher primary vote.

In the last two decades, Labor’s first preference support has trended down largely because of the growth in Green support. The strong flows of Green preferences to Labor, and Labor to the Greens where counted, means that support for the two parties can almost be treated as a block, in the way we tend to ignore the increasingly rare three-party contests between the Liberal and National Parties.

If the Coalition trails Labor’s first preference support then Labor is best placed to win. The Coalition did trail on 39.5% in 1998 to Labor’s 40.1%, but the Coalition won that election with 49.0% of the two-party preferred vote through the vagaries of electing parliaments from single-member electorates.

Labor trailed 4% in 1990 and won narrowly, and trailed by 5.3% in 2010 and won narrowly. That Labor can win from behind as in 2010 comes down to the strong flows of Green preferences.

The 2019 election was interesting in that there was an increase in non-Green third party voters giving preferences to to the Coalition, or as shown in the graph below, of fall in the proportion giving preferences to Labor. That’s largely because of stronger flows of One National and UAP preferences to the Coalition than at previous elections. Whether that was a consequence of the 2019 election campaign or a longer term trend may be revealed by the 2022 election.

The above graph is taken from a previous post where I broke down preference flows from the 2019 election.

Detail on Composition of Two-Party Preferred Vote

Note: All percentages are calculated as a percentage of total formal vote.

Preference flows at the 2019 Election

Below is a summary graph of the same data that I published in my previous post on preference flows at the 2019 election.

2019 Two-Party Preferred by Vote Type

The graph below shows the two-party preferred vote by vote type at the 2019 election. As the graph shows, Labor won a narrow majority in the two categories of votes cast on election day, Ordinary votes (50.4%) and Absent votes (53.6%). But the election was decided before election day, the Coalition winning clear majorities with Pre-Poll votes (53.8%) and Postals (57.6%), all adding up to an overall 51.5% for the Coalition once all the votes were counted.