Wentworth has clearly evolved into a three-horse race, with independent Licia Heath apparently having failed to gain much traction, despite some high profile backing. Liberal candidate Dave Sharma is all but certainly to lead the primary vote, but a lot depends on who finishes second out of independent Kerryn Phelps and Labor’s Tim Murray. So far as the excitement of election night is concerned, a lot equally depends on which two candidates the Australian Electoral Commission picks for the notional two-candidate preferred count. I would assume they will play it safe, follow tradition and conduct the count between Liberal and Labor, but we won’t actually know until polls close tomorrow. If they get it wrong, we will be relying on word-of-mouth accounts from scrutineers, which are sure to be widely propagated on social media, for even a vague idea of how things are playing out. That’s assuming the result is not so close as to make it unclear who out of Phelps and Murray ends up ahead – and this too will depend in preferences, on which we will likewise have no official guide on the night.
There has been a lot of cultural warfare going on in the left about the Greens’ decision to direct preferences to Labor ahead of Kerryn Phelps, which raises the bar for her to get ahead of Labor, and by extension reduces the chances that Sharma will lose. However, the effects of the Greens how-to-vote card are a lot more modest than some of the party’s enemies are trying to make out. Indeed, the effect of how-to-vote cards across the board is likely to be pretty muted in an electorate as educated and politically engaged as Wentworth. For an inkling as to how preferences are likely to flow, the best bet is to look at the data available from similar by-elections in the past (certainly it is likely to offer a better guide than the respondent-allocated preference flow in this week’s Greenpeace/ReachTEL poll, which implausible had the flow of preferences to Phelps at over 90%). Unfortunately, exact precedents for this particular by-election are hard to identify.
Going back the last three electoral cycles, I count six federal contests in which Liberal candidates squared off against independent or non-Greens minor party candidates at the final count, excluding those in which the situation was complicated by the Nationals. Four involved the Nick Xenophon Team or its successor, the Centre Alliance (that being the Mayo by-election on Super Saturday), which offers a less than exact parallel. The other two were the North Sydney by-election in 2015, which is very useful, and Cathy McGowan’s win over Sophie Mirabella in Indi in 2013. At state level, New South Wales and Queensland precedents have been of limited value due to optional preferential voting, and nothing in recent history quite fits the bill from Victoria.
The flows of preferences between the Liberal and non-Liberal candidates in these electorates is shown in the table above. Xenophon’s share of preferences from Labor was in the seventies, but Cathy McGowan’s approached 90% — presumably the latter is a better guide. For the Greens and “others”, North Sydney is a particularly useful precedent, suggesting Phelps would get about three-quarters of Greens preferences and a little more than half of everybody else’s. However, I would imagine the former figure especially is too low, given the nature of the candidates involved (Trent Zimmerman versus Stephen Ruff, as opposed to Dave Sharma versus Kerryn Phelps). So I could perhaps speculate that Phelps, assuming she finishes second, will get about 85% of Labor preferences, maybe 80% from the Greens, and about half the remainder. On that basis, Dave Sharma wouldn’t want to fall below 40% if he’s squaring off against Phelps.
Subjects I will hopefully probe into later, time permitting: how the minor candidates preferences are likely to flow between Sharma, Phelps and Murray; and how far Sharma’s primary vote would have to fall to put him in jeopardy from Labor.