Prior to the election, I drew attention to the differences between my calculations and those of the AEC for a number of non-classic seats that gained new areas during the redistribution. Originally I had a list of 14 affected seats, but one of them (Nicholls) has reverted to a classic contest.
There’s a variety of reasons why the AEC’s estimated margin in these seats is wrong. Antony explains the reasons here, and I also explained them here.
For this post, I wanted to take those adjusted margins, and publish a list of what I think the actual swing is in these seats. In some seats the difference is quite small, but in others it’s a lot larger.
The difference between my estimated margins and Antony’s estimated margins are quite small. In six seats we produced the same number at one decimal point. Eleven out of thirteen seats have the margins within 0.6% of each other.
The two exceptions are Kooyong (I had 3.5%, Antony had 2.2%) and Wentworth (I had 9.0%, Antony had 6.8%). I have since become convinced that Antony’s number is more accurate in Wentworth. If you take Antony’s figure, the swing in Wentworth is similar to the other teal seats. If you take mine, Spender instead has a swing against her. I think the 6.8% figure makes more sense. So I’ve used that, but otherwise used my margins.
My margins suggest that the swing against the Melbourne teal independents was a bit bigger than the AEC margins. My margins make the swings to the independents in Bradfield and Mackellar are smaller, but Warringah’s swing is bigger. The AEC’s margin suggests that Wentworth was a notional independent seat, with a massive 8.9% swing. Antony’s margin instead implies a 1.5% swing.
There are notable differences for the Greens. My margin suggests a small swing against the Greens in Grayndler, not a swing towards them. It also increases the size of the swing against the Greens in Melbourne.
The swing to the Greens in Wills is also substantially smaller with my margin. The real swing is more like 3.2%, not 7.6%. The 7.6% margin is based on not properly factoring in the strong Greens vote in the areas added to Wills from Melbourne.