Last week Stats NZ released the first tranche of data from the 2023 Census, an exciting milestone for anyone with a thirst for regional or socioeconomic data. With the prior Census held in 2018, this represents the first Census data since the start of the COVID-19 pandemic. In this article, we dive into the first tranche of data, explain why the good stuff is yet to come, and raise a note of caution for population comparisons with the first tranche of data.

The first tranche of Census data included a handful of high-level indicators down to a territorial authority (and Auckland local board) level only. This tranche included population (Census usually resident population, CURP) by age, high-level ethnicity, and Māori descent, as well as dwelling counts.

New Zealand’s population continues to become more ethnically diverse, with the share of the population identifying with European ethnicity easing from 70% in 2018 to 68% in 2023. The population identifying with Māori ethnicity has risen from 17% to 18%, and Pacific peoples from 8% to 9%. The population identifying with Asian ethnicity has risen from 15% to 17%, almost equal in size to the Māori population.

As an aside, people writing in ‘New Zealander’ as their ethnicity made up 78% of the ‘Other’ ethnic group in 2018, and even higher shares in prior years. It’s encouraging to see the ‘Other’ group ease further in 2023 as this suggests the trend of writing ‘New Zealander’ is waning, in turn making the ethnicity data more meaningful for analysis.

With disruption to migration and population growth through the pandemic, and an over-stimulated residential construction sector, we added dwellings faster than we added population over 2018 to 2023. Nationally, our dwelling stock grew 9.0% between 2018 and 2023, based on 2023 Census data, although this does include growth in unoccupied dwellings (with delineation of unoccupied dwellings coming in later Census tranches).

Our population rose 6.6% over the same period, according to Stats NZ’s subnational estimated resident population (which is yet incorporate the 2023 Census – more on that later). At a glance, dwelling growth outstripping population growth suggests that we’ve made inroads our housing shortfall, although we’ll need more detailed data on dwelling occupancy to quantify the shortfall that remains.

Auckland faced the widest gap between dwelling and population growth – with 11.9% growth in dwellings over 2018 to 2023, more than double their population growth of 5.1%. We have previously estimated that the undersupply of housing in Auckland was sizable.

In Wellington Region, the number of dwellings grew 6.4%, ahead of population growth of 4.7%. However, across the rest of the North Island, the population grew as fast or faster than dwellings.

Across the South Island, all regions experienced faster dwelling growth than population growth, although there was a fine margin in Otago Region.

Exciting as this first tranche of Census data is, a bit of patience is required. The most substantive release is scheduled for October, with data on individuals and dwellings released down to sub-district level (SA1 and SA2 areas). Data on families and households then follows in November. Further releases will come throughout 2025, with topics such as work, income, education, transport, smoking towards the back of the rank.

Despite the obvious excitement around new Census data, finding out what the 2023 Census means for your population growth is a case of hurry up and wait. The Census numbers released last week are what’s know as the Census usually resident population (CURP) – the number of people who live in each area, that usually live in that area, and either filled out a Census form or were imputed using other data sources. The CURP figure doesn’t account for people who skipped the Census and couldn’t be counted otherwise. Stats NZ runs a post enumeration survey (PES) to understand how many people slipped through the cracks. And there can be enough of this group to move the figures.

The 2018 Census counted a total of 4.7 million residents (the Census usually resident population). However, the subsequent post enumeration survey estimated that the Census missed 171,800 people, and counted 46,700 people more than once, meaning that the Census undercounted the population by a net 124,800 people. Reflecting the estimated undercount, and some timing differences, the estimated resident population (ERP) for New Zealand’s population as at 30 June 2018 was 4.9 million (Chart 3).

Because the Census usually resident population doesn’t count everyone, it is standard practice to use the estimated resident population instead, especially for regional analysis. Stats NZ publishes the estimated resident population on a subnational basis around October each year, so we already have population estimates for 2023. However, the 2023 population estimates don’t take into account the 2023 Census, yet. Currently, the population estimates use a combination of Census data up to 2018, coupled with more recent administrative data on births, deaths and net migration.

Stats NZ is planning to revise its population estimates for 2019-2023 in early 2025, to incorporate both the 2023 Census and post enumeration survey. Until then, we won’t know how their estimates for 2019-2023 were tracking, and therefore won’t know how any population projections based on them have tracked. In the meantime, it’s important to avoid making an apple (Census usually resident population) and banana (estimated resident population) comparison.

In the past, these revisions to the ERP are generally relatively minor – typically less than plus or minus 1% at a territorial authority level, which reflects that Stats NZ has a good handle on the population through administrative data. Larger revisions are to be expected at a sub-district level, reflecting the challenges of accurately geolocating individuals, particularly those that move frequently within a district.

Although last week we received our first Census insights since 2018, more recent estimates from a range of sources are already available. For high-level, timely insights, our Quarterly Economic Monitor provides indicators up to the March 2024 quarter including employment, NEET rates, etc. For more in-depth insights, our Regional Economic Profile includes insights up to the March 2023 year, ranging from population by age, population by ethnicity, household incomes and occupation.

Our team is currently focusing on rebuilding our Census Community Profiles in a new home within the Regional Economic Profile. The new Community Profiles will feature significantly enhanced functionality and a wider range of Census variables. We are planning to release the new REP Community Profiles later this year once the more fulsome Census datasets have been released, and will be in touch with clients to let them know when it’s coming.

Stats NZ is currently consulting on the future of the Census. There are a range of drivers of this – better availability of administrative data sources, challenging Census participation rates, and ever-increasing costs of running an all-at-once national survey with boots on the ground. There are a range of options available – using administrative data sources, running a rolling Census, running more targeted surveys. Stats NZ already publishes an experimental Administrative Population Census, which would be a promising substitute for many Census questions. The annual estimated resident population is a good example of what is possible using predominantly administrative data.

Our team of economists is here to help you figure out what the Census means for your area and organization. Please get in touch with your client contact or info@infometrics.co.nz if you have any questions.