The influence of age on party vote preferences

We all instinctively know that age has an influence on which parties people vote for. So I thought it'd be an interesting exercise to visualise the relationship between voter turnout by age and party votes in each electorate.

By using the age segments from my analysis of the youngest, oldest, most and least representative electorates, I've compared how electorates with above average shares of each of those segments voted relative to the overall party vote average (not the total party vote share) across the country.

The results are much as you'd expect, National is skewed towards voters aged 50 and over, Labour is skewed towards voters 49 and under. NZ First mimics National but with a much greater spread, and a similar situation presents itself for the Greens mimicking Labour. For the Māori Party I've only looked at General Electorate seats, largely because in the Māori Electorates there's not much of a difference between each of the electorates in terms of age segments. TOP I included only after I realised that their increased support in the 18-34 segment was interesting from the perspective that in Wellington Central and Ōhāriu, they would have been competing more with Labour and the Green Party for those votes, than they would have been with National or NZ First.

You could in theory argue that these numbers represent a likelihood of a certain age segment to vote a given way, but I think they're only indicative of that, as there are other factors at play, e.g. urban vs rural, affluent vs deprived, tertiary educated vs those without degrees, that will also influence these.

Even so, it helps contribute to our overall understanding of the electorate and how it voted this election.

In electorates with an above average share of Youth voters (those aged 18-34), National on average performed 11.01% worse (around 5.10 percentage points) than they did on average across the country. For Labour they performed on average 14.68% better in these electorates (5.25 percentage points) than nationally. The big differences though were NZ First who under performed here by 23.59%, and the Greens and Māori Party who over-performed by 20.87% and 22.18% respectively. As shown in the first graph, TOP's support, while having less of a spread than the other parties, over-performed in this segment.

Unsurprisingly, as our voters become older and we enter the Mortgage and Family segment, National still under-performs, but only by 2.88%, while Labour over-performs by 7.22%. NZ First and the Māori Party both still struggle in this segment (though I'd caution against assuming that these are representative of the Māori Party's support given the vast bulk of their support does come from the Māori Electorates). Interestingly, the Mortgage and Family was TOP's worst performing segment, coming in at 7.36% worse than there national average.

The Empty Nest segment - those aged 50-64 - is the first time we see National and NZ First over-performing their national average, by 7.07% and 14.73% respectively. Labour, the Greens and Māori Party all drop off from our prior segment as well. What I think is really interesting is how dramatic NZ First's support shifted between the Mortgage and Family segment and the Empty Nest Segment.

The Super segment - those aged 65 and over - sees NZ First get the lion's share of its votes. National, on the other hand, actually fairs slightly worse than it did in the Empty Nest segment, getting just 6.63% more of the party vote on average. What's also interesting here is that both National and Labour's support didn't move as radically as it did as we went through the other segments. National was obviously hurt by some support going to NZ First, but Labour doesn't seem to have suffered as you might expect they would looking at how the Green Party went. TOP's support, while still down on their national average, was better than their Empty Nest segment support though.

Hopefully I'll be able to do a bit more in-analysis of each of the age brackets that the Electoral Commission uses. But five graphs are easier to produce than twelve!