Voter preferences

Party vote performance in each age bracket

The most competitive market for votes in New Zealand is for those aged between 45-49, with National, Labour, the Greens, and the Māori Party all receiving, on average, similar shares of the party vote in electorates with above average shares of people in this age range.

Spurred on by my other recent work looking at voter turnout by age segments and how representative that made electorates, and how those age segments were more, or less likely to vote (indicatively at least), I thought I'd take the plunge and look at each party individually across all the Electoral Commission's age brackets that they collect data on, to see if it revealed any other insights.

What it's revealed is that while National and NZ First, and Labour, the Greens and the Māori Party might be poles apart in terms of their popularity with voters aged 18-34, such a big gap in voter preference based on age doesn't appear to manifest itself beyond 35 years old, starting to converge from its largest difference at 30-34-years-old, bar for the Green Party, Māori Party, and NZ First.

As I said in the introduction, it's interesting how at the 45-49 mark, National, Labour, the Greens and the Māori Party all converge, with all getting more or less similar party votes from electorates with an above average representation from this age bracket as they did on average across all the General Electorates. Though I'd caution here that as this analysis excludes the Māori Electorates (due to their big youth skew and low deviation among the seven electorates), that the Māori Party figures here should be taken with a grain of salt.

Also keep in mind that as you read through the following graphs, they do have different scales on the Y axis, so movements may be more pronounced in these than they are on the top comparitive graph.

National's worst performing age group appears to be the 30-34 bracket, though it under-performed on average in electorates with above average shares of voters under 44 to varying degrees, with it being weighted towards those electorates with above average shares of those aged 34 and under being the least likely to vote National. National also has the second most narrow deviation range in this analysis, with only The Opportunities Party doing better.  National's support is weighted towards those aged 45 and over, and peaks at those aged 65-69. In part, this larger likely support from older voters, who both enrol and vote at higher rates and in greater numbers than other age groups, no doubt contributed significantly to National's end result of 44.4%

As you'll see later, with NZ First doing so well with voters aged 55 and over, National can, in the short term at least, reinforce their vote by targeting NZ First's supporters. Longer term however, National will need to find a way to both preserve their strength in covers aged 50 and over, as well as doing a better job of appealing to younger demographics too.

Labour's graph in many ways is the mirror image of National's, albeit slightly more pronounced in its over and under-performance in the age brackets. The 30-34 age bracket is again interesting, as not only was this where National was most likely to perform worst, it's also where Labour performed best. Where National's deviation was relatively narrow, Labour's is much more pronounced, though it ranks in the middle of the six parties we're looking at in this. While Labour's support amongst youth voters is very strong, to offset the advantage that National gets from older voters, they would need much higher enrolment and turnout rates than they got even this election.

In news that will shock no one, New Zealand First's support overwhelmingly comes from those aged 55 and over, but especially those aged 60 and over. Because of this, NZ First has the largest deviation of any of the six parties in this analysis. NZ First and Winston Peters focus heavily on courting this demographic, so it's no surprise that they rely so heavily on support from them. It also begs the question that once NZ First loses its trump card for reaching them - Winston Peters himself - how are they going to manage going forward, as nobody else in the party seems able to capture that audience in the same way that Winston Peters does.

The Green Party have the second biggest deviation for their support after NZ First, and they're very much the opposite story to them too. Massive support across voters aged 39 and under, but this plummets to their average for those 40-44, before briefly rebounding for those aged 45-49, and not recovering beyond those aged 55 and over. Where the Green Party has an opportunity is to stop that leaching of support between people aged 35 years old and 44 years old, though in doing so they're likely to take voters from Labour.

As I wrote earlier, it's important to take these figures for the Māori Party with a grain of salt. This analysis is based off General Electorate votes, and with the Māori Party support coming from the Māori Electorates, which are much more heavily skewed towards younger voters than the General Electorates are, isn't representative of what's going on. That being said, given the skew in Māori Electorates towards younger voters, it probably suggests that this graph might be even more weighted to young voters. If there is one thing the Māori Party could take from this, and my earlier work, is that there's an opportunity with a big cohort of young Māori voters for them to win over between now and 2020.

The Opportunities Party is a bit of an interesting one in that because their vote was so heavily centralised around the Wellington region, it's likely the main influence on how this graph looks. TOP has done well with those aged between 18-29, and to a lesser extend those aged 30-34, and worst with those aged 40-49. National and TOP's support seems to switch at around age 39/40, while they bisect the rest of the parties between 49 and 54. Again, it's hard to read too much into these figures for TOP other than the fact that their deviation was the smallest among all parties.


As I said in looking at the possible influence of age on party voting preferences, it's very tempting to claim that these graphs show the likelihood of different age brackets voting for different parties - e.g. those aged 18-24 are 8% less likely to vote for National than the average New Zealander, and they're 11% more likely to vote for Labour. I think this data hints at that possibility, but without exit polling - which is illegal in New Zealand - it's impossible to know this for sure.

Where I think this data is very useful is using it to frame your thinking about where the parties position themselves in terms of their core support, and where they see the main battlegrounds are in terms of competing for votes from other parties. From around 30-years-old - where most of the parties graph lines start their journey towards converging on their national average - to the 50-54 bracket - where after that they diverge again, demonstrates I think that for the most part, the parties see voters within that 20 year age group - 30-years-old to 54-years-old - as the swing voters they need to target.

NZ First is the only really noticeable exception to this rule, but that's largely because Winston Peters has progressively clawed out those on NZ Super as his target voter base.

If you think generally about people in that 30 to 54 age range (and I'm talking very generally here) they're buying houses, getting married, having kids, they're likely to hit their career peak around between 40 to 49 (there's some US data around this, and sadly it has women's pay peaking at 40, and men's 49, highlighting again the gender pay gap). Retirement, while we're being constantly reminded about saving for it, is still a long way off, and the more immediate concerns are paying the mortgage or rent, affording school, doctors visits, dealing with health issues that become more and more likely to crop up, having a job, getting pay rises and getting ahead in life, and so on. Most have either finished up their travelling plans, or are about to, and are probably focused more on things like family or careers.

If you keep all this in mind, it starts to give you a bit of a picture of how and why political parties position themselves the way they do. In many respects they have to ensure their base votes for them, but they also have to reach out to that big segment of 30-to-54-year-olds to win their votes too.

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!