Estimated resident population 2023: Data sources and methods describes the data sources and methods used to produce the 2023-base estimated resident population (ERP) at 30 June 2023. It includes descriptions of the data sources and methods used to estimate the contributing components at national and subnational levels, by age, sex, level 1 ethnic groups, and Māori descent. The report is aimed at technical users who want to gain an understanding of the magnitude and quality of the contributing components used to produce the ERP at 30 June 2023.
Summary
The 2023-base ERP of Aotearoa New Zealand is an estimate of all the people who usually live in New Zealand at 30 June 2023. The ERP is derived from the 2023 census usually resident population count with adjustments for net census undercount, residents temporarily overseas, and estimates of population change due to births, deaths, and migration between census night (7 March 2023) and the mid-year reference date (30 June 2023).
In this report, we describe the data sources and the methods used to estimate each of the components, the methodological steps for compiling the ERP, and the adjustments included in the ERP. While the methods to compile the ERP in 2023 have remained largely consistent with those followed in 2018, some changes have been introduced due to the extended use of administrative (admin) data. For example, linking of the 2023 Census and ERP components in Stats NZ's Integrated Data Infrastructure (IDI) enabled us to share attribute values across the different components.
All population measures, including census counts and population estimates, have some uncertainty around them. This report also describes the methods and the contributing data sources we used to measure the uncertainty around the ERP at 30 June 2023.
The process to compile the ERP included using admin data sources and census coverage results. Admin data has always been used in population estimation, and this has been extended to strengthen the accuracy of the 2023-base ERP. In summary, the ERP has been compiled by:
- using the 2023 Census dataset that had been created by combining census forms and admin data (Methodology for using admin data to count people in the 2023 Census)
- using the results of net census undercount as measured by the Post-enumeration Survey (2023 Post-enumeration Survey: Methodology)
- accessing linked admin data and 2023 Census data in the IDI to obtain information on resident location, ethnic group, and Māori descent where not otherwise available
- accessing linked address notifications data in the IDI for estimating internal migration to and from geographic areas between census and mid-year
- deriving natural increase from birth and death registrations, which included information about resident location, ethnic group, and Māori descent
- accessing linked border movements for identifying migrant arrivals and departures between census night and mid-year using the outcomes-based migration measure (Outcomes versus intentions: Measuring migration based on travel histories)
- including an adjustment to the ERP at 30 June 2023 of children (aged 0-14 years) as a reconciliation of the differences in demographic estimates from admin records and ERP for these ages. The demographic reconciliation was based on admin records of births, deaths, and international migration.
Enquiries
Kim Dunstan
[email protected]
ISBN 978-1-991307-58-3
