Which seats may change hands

On Patreon (paywalled) I write:

In this post, I look at which electorates may change hands, based on the change in party vote since the election.

Often any analysis is done using a simple two party swing, but that doesn’t take account of the fact that the change in support for minor parties also can impact an electorate race.

So what I have done is take the split vote analysis for each marginal electorate. Below is Hamilton East

So the National candidate got 65% of ACT voters, 30% of NZ First voters, 88% of National voters etc.

I then look at how much the nationwide party vote has changed since the election, based on an average of recent public polls.

The difference in the current polls from the election results is multiplied by the 2023 party vote for each marginal electorate to project the party vote for that electorate today. So in Hamilton East National got 42.9% in 2023. You multiply that by 29.2%/38% and get a projection of 32.9%. Then you apply the split vote analysis to project the candidate vote on the projected party vote.

This is just a data model. It is not a prediction. It doesn’t take account of factors such as how the incumbent MP has done, who the opposing candidate will be, new boundaries, a change in split voting etc. It should be seen more as looking backwards at 2023, and saying what the outcome would have been then based on the current party vote polls.

I will work on a model which takes account of the new boundaries. This is challenging as the split vote data is only available at electorate level.

But for now, here is what seats Labour on paper would now lead in, based on the change in the party vote (remainder behind the paywall)