In a remarkable display of synchronicity, yesterday saw the announcement of finalised new federal electoral boundaries for Victoria, which will be followed today by the publication of draft new boundaries for Victorian state boundaries, the result of an entirely separate process. While the former release is limited to written descriptions of the changes that have been made to the draft that was published in March, with maps and geospatial data not to be published until July 28, I have taken the effort to conduct a full analysis of the final boundaries, which you can read about below. I hope to be able to provide an analysis of the state boundaries later (probably much later) today.
The federal redistribution gives effect to an increase in Victoria’s representation from 38 House of Representatives seats to 39, at the expense of Western Australia, which is down from 16 to 15 and has accordingly undergone its own redistribution which was finalised a fortnight ago. The final boundaries in Victoria make changes to the draft boundaries affecting 20 electorates, by far the most significant of which is the abandonment of a major adjustment that was proposed for the boundary between Macnamara and Higgins in Melbourne’s inner south, an area of particular interest to the Greens.
N.B.: I am a little confused by the assertion of the AEC release that a remnant of the change remains in that most of Windsor has been transferred to Higgins, as it seems to me that both draft and final boundaries have this suburb remaining entirely in Macnamara. This analysis proceeds on the assumption that this statement is in error, but I may well be missing something. Ben Raue’s maps of the draft boundaries at The Tally Room are instructive here. (UPDATE: This has finally penetrated my skull — Windsor will indeed be transferred to Higgins, with effects that do little to disturb my overall analysis. The spreadsheet linked to at the bottom of the post has been revised to reflect this).
The practical upshot of the reversal is that the Greens are now less likely to take Macnamara from Labor, but the chances of them rather than Labor taking Higgins from the Liberals has increased, without much affecting the Liberals’ overall chances of losing the seat. The draft proposed a straight north-south boundary along Williams Road, resulting in Macnamara gaining territory around South Yarra at the northern end, while an area around Caulfield in the south was to go the other way. This would have boosted the Greens in Macnamara by around 2% from their 24.2% at the 2019 election, drawing in roughly equal measure from the Liberal and Labor vote. Just a few days ago, this prospect had the Greens talking up their chances of taking the seat from Josh Burns, who retained it for Labor when Michael Danby retired in 2019.
Macnamara, which was known prior to the 2019 election as Melbourne Ports, has been in Labor hands since 1906, but has lately evolved into a tight three-way contest involving the Liberals, who came within 2.2% of winning the seat in 2016, and the Greens, who would almost certainly win if they were able to reduce Labor to third place. This they fell 5.8% short of doing so in 2019, when they were excluded at the second-last count with 27.33% of the vote to Labor’s 33.2%. Greens preferences then flowed heavily enough to Labor to secure a comfortable 6.2% margin for Josh Burns, despite the Liberals outpolling him by 37.4% to 31.8% on the primary vote. The changes proposed by the draft boundary would have brought the Greens’ shortfall to around 3%, in a seat where their primary vote had steadily escalated from 15.0% to 24.2% since 2007.
However, the Greens’ gain in Macnamara would have been balanced by a weakening in Higgins, which on my analysis would have cut their primary vote by 1.6% while boosting Liberal and Labor by 0.7% each. Higgins has also developed into a three-cornered contest in recent years, a particularly notable fact in a seat that the Liberals have held since its creation in 1949, with members including John Gorton and Peter Costello. The Greens came closer to taking second place in Higgins in 2019 than they did in Macnamara, being excluded from the count with 24.3% to Labor’s 26.2%. However, the Liberals only fell just short of a majority at this point with 49.5%, and would have picked up enough stray preferences after the final exclusion to have retained the seat in any case.
Preference flows in Melbourne’s inner urban seats in 2019 suggest the Liberals would be slightly more likely to lose Higgins if Labor rather than the Greens made the final count, since flows from the Greens to Labor were slightly stronger than vice-versa — particularly in Macnamara, where Greens preferences split 87.5-12.5. However, the distinction seems to blur in areas where the Liberal vote is stronger, with Greens preferences in Higgins splitting 83.4-16.6, which was equal to how Labor preferences split between the Greens and the Liberals after they finished third in Kooyong.
The only other change to the finalised boundaries that might potentially have a bearing on the election result involves Chisholm, Higgins’ eastern neighbour, which Gladys Liu retained for the Liberals in 2019 by 0.6% after a 2.3% swing to Labor. The seat will be reoriented southwards with the redistribution, which by my reckoning added 0.2% to the Liberal margin on the draft boundaries — although Antony Green’s calculation was that it had in fact gone 0.4% the other way. My assessment is that the minor adjustments made in the final boundaries boost the Liberals by a further 0.3%.