With the flood of post-election analysis having subsided and opinion polling yet to properly crank up again (expect that to change when parliament resumes next week), there is not a lot to report. Roy Morgan’s weekly video update last week informed us that Labor leads 53.5-46.5 in its latest round of polling, out from 53-47 the last time it offered a full set of results in the middle of last month, but it didn’t deem fit to offer anything further. The international leadership approval tracking poll by Morning Consult suggests Anthony Albanese’s standing has continued to improve, his approval having cracked 60% and disapproval down to 24%, which compares with 57% and 26% when I last reported on it three weeks ago.
I do have another new entry to relate from the burgeoning field of online psephological tools, courtesy of Alex Jago and Ben Messenger, providing a triangular representation of the increasingly common occurrence of three-cornered contests between Labor, the Coalition and the Greens. This can just as easily be adapted to any combination of three parties or candidates you care to choose, as long as you have a reasonable handle on how preferences are likely to flow between them.
The starting point here is each party’s share of the vote at the second last preference count, to be identified henceforth as 3CP, or three-candidate preferred. The tool’s default preference splits are 80-20 against the Coalition when Labor or the Greens are excluded, roughly consistent with all past experience, and 70-30 in favour of Labor when the Coalition is excluded, which is about what happens when Coalition preferences are so directed. On the last relevant occasion I can think of when they went the other way, when Adam Bandt first sought re-election in Melbourne in 2010, they favoured the Greens 80-20. Happily, the tool allows you to set the splits however you desire.
To explain what’s going on here, I’ll stick with the defaults. The Coalition 3CP is on the x-axis, the Greens are on the y-axis, and the balance belongs to Labor. On the left we see the 3CP needed by the Greens to defeat Labor when the Coalition is uncompetitive, starting at 50% where the Coalition has no votes at all. At this end of the triangle, the dividing line between a Greens win and a Labor win is broken into three parts. As the Coalition’s 3CP increases from nothing to 29%, the Greens’ required 3CP falls gently from 50% to 42% while Labor’s falls sharply from 50% to 30%, reflecting Labor’s higher share of Coalition preferences.
Once the Coalition gets to 30%, they reach the point where they might make the final count in a race where both Labor and the Greens are competitive, without being competitive themselves. Such was the case in Brisbane and Macnamara at the May election, which is why the AEC conducted indicative 3CP counts to provide an early indication of who would ultimately win there out of Labor and the Greens. As this presents the Greens with a new winning scenario where Labor runs third, here their minimum winning 3CP quickly falls from from 42% to 34%. But once the Coalition 3CP is significantly over a third, there is no longer enough left over for both the Greens and Labor to be competitive. Here the 3CP needed by either reduces from 34% to 29% as the Coalition 3CP increases from 34% to 44%.
With the Coalition only receiving 20% of preferences, they need fully 45% on 3CP to be in contention themselves. Even here they only make it if the remainder splits about evenly between Labor and the Greens, since the preferences they receive diminish together with the 3CP of whoever out of Labor and the Greens drops out. From that point on, the Coalition’s chances steadily increase to 100% where their 3CP reaches 50%, at which point they win before Labor or the Greens are excluded.