Subnational Ethnic Population Projections 2018-base

Reference period This release contains the 2018-base projections for four broad and overlapping ethnic populations usually living in New Zealand's 16 regional council areas (regions), 67 territorial authority areas (TAs), and 21 Auckland local board areas (LBAs). Projections are available for: 'European or Other (including New Zealander)', Māori, Asian, and Pacific. Each ethnic population consists of all people who identify with ethnicities within that broad ethnic group. People who identify with more than one ethnicity are included in each ethnic population they identify with. The projections supersede the updated 2013-base projections released in October 2017. The new projections have the estimated resident population of each ethnic group at 30 June 2018 as a base, and cover the period to 2043 at five-year intervals. Consistency with other projections These subnational ethnic population projections complement the New Zealand projections of ethnic populations National Ethnic Population Projections: 2018(base)–2043 released on 28 May 2021. However, only the median projection (50th percentile) of the national ethnic population projections and the medium projection of these subnational ethnic population projections are directly comparable. Other percentiles or projections cannot be directly compared because projection assumptions may be incompatible. These subnational ethnic population projections also complement the projections of subnational total populations Subnational Population Projections: 2018(base)–2048 released on 31 March 2021. However, only the medium projections of each are directly comparable. Other projections cannot be directly compared because projection assumptions may be incompatible. Changes since the previous 2013-base projections Review of assumptions Deriving these projections involves reviewing all projection assumptions for each area and each ethnic group. These subnational ethnic population projections are updated to incorporate the latest demographic information, notably the 2018-base Subnational Population Projections (released 31 March 2021) and the 2018-base National Ethnic Population Projections (released 28 May 2021), which both incorporate results from the 2018 Census of Population and Dwellings and subsequent population estimates. Birth and death registrations and migration data are also important data sources. Geographic classification The population projections in this release are based on regional council, territorial authority, and Auckland local board classifications and boundaries as at 1 January 2021. Projection assumptions Projection assumptions are formulated after the analysis of short-term and long-term historical trends, information provided by local planners, and government policy. Base population These projections have the estimated resident population of each area and each ethnic group as at 30 June 2018 as a base. This population was based on the census usually resident population count of each area and each ethnic group as at 6 March 2018, and have been adjusted for: People missed or counted more than once by the census (net census undercount) Residents temporarily overseas on census night Births, deaths, and net migration between census night (6 March 2018) and 30 June 2018 Reconciliation with demographic estimates for ages 0–14 years The Estimated resident population (ERP), adjustments to derive ERP at 30 June 2018 (from census usually resident population) table in NZ.Stat summarises the ERP, and adjustments used to derive the ERP, for each area and each ethnic group. Fertility and paternity New birth cohorts are added to the population by applying fertility assumptions to the female population of childbearing ages (12–49 years) and paternity assumptions to the male population (15–54 years). The paternity rates allow for births that men of a given ethnic group have with women not of that ethnic group. For example, Māori paternity rates allow for births that Māori men have with non-Māori women. The assumed fertility and paternity rates for each area and each ethnic group are based on registered births during the period from 2018–21, and changes which are consistent with fertility and paternity assumptions from the National Ethnic Population Projections: 2018(base)–2043. Under the national median assumption, the total fertility rate decreases between 2019 and 2043 for the: 'European or Other' population, from 1.72 to 1.60 births per woman Māori population, from 2.13 to 1.85 births per woman Asian population, from 1.40 to 1.39 births per woman Pacific population, from 2.19 to 1.90 births per woman Under the national median assumption, the total paternity rate decreases between 2019 and 2043 for the: 'European or Other' population, from 0.14 to 0.12 births per man (with non-European and non-Other women) Māori population, from 0.79 to 0.60 births per man (with non-Māori women) Asian population, from 0.14 to 0.11 births per man (with non-Asian women) Pacific population, from 0.86 to 0.64 births per man (with non-Pacific women) Fertility and paternity assumptions are derived for the purpose of creating projections for each population and should not be used as a precise measure of fertility or paternity differentials between areas or ethnic groups. These projections allow for births to parents of each ethnic group that are not registered as children of that ethnic group. The medium assumed loss factor is 1.5 percent for 'European or Other', 3.6 percent for Māori, 1.9 percent for Asian, and 2.8 percent for Pacific. Low and high assumptions for fertility rates, paternity rates, and loss factors are chosen to represent plausible alternative fertility and paternity scenarios for each area and each ethnic group. The projections allocate births between males and females. A sex ratio at birth of 105.5 males per 100 females is assumed for each area and ethnic group, based on historical data. Mortality Mortality assumptions are applied to each age–sex group to allow for deaths. The assumed mortality rates for each area and ethnic group are based on registered deaths for each area during the period from 2018–21 and changes that are consistent with the mortality assumptions from the National Ethnic Population Projections: 2018(base)–2043. Under the national median assumption, period life expectancy at birth increases between 2019 and 2043 for the: 'European or Other' population, from 81.3 to 84.5 years for males, and from 84.7 to 87.8 years for females Māori population, from 73.6 to 79.5 years for males, and from 77.3 to 83.0 years for females Asian population, from 85.0 to 87.0 years for males, and from 87.9 to 89.5 years for females Pacific population, from 75.3 to 81.8 years for males, and from 79.3 to 85.1 years for females Mortality assumptions are derived for the purpose of creating projections for each population and should not be used as a precise measure of mortality differentials between areas or ethnic groups. Low and high mortality assumptions are chosen to represent plausible alternative fertility and paternity scenarios for each area and each ethnic group. Migration Migration assumptions are applied to each age–sex group to allow for net migration (arrivals minus departures). Migration at the subnational level has both an internal (to/from other areas of New Zealand) and an external (to/from overseas) component, although these separate components are difficult to quantify. For example, ethnicity is not collected in external migration data. The assumed net migration levels and age–sex patterns for each area and ethnic group are based on a consideration of: the observed net migration during each intercensal period from 1996 to 2018 the capacity of each area for further growth (for areas with net inflow) whether historical outflows can be sustained (for areas with net outflow) the information available from and about local authorities relating to current and future developments that may affect population change the latest migration assumptions from the National Ethnic Population Projections: 2018(base)–2043 and the Subnational Population Projections: 2018(base)–2043 Migration assumptions at the subnational level generally reflect the assumptions at the national level. Migration assumptions reflect average annual net migration over the period, although annual net migration can be expected to vary from year to year. Low and high net migration assumptions represent plausible alternative migration scenarios for each area and each ethnic group. They therefore do not sum to any specific national total. Inter-ethnic mobility Inter-ethnic mobility (IEM) assumptions are applied to each age–sex group to allow for the net effect of people changing their ethnic identification over time. IEM assumptions are the same as those used in the National Ethnic Population Projections: 2018(base)–2043. Under the national median assumption, there is an average net change to the population from 2019–43 due to people changing their ethnic identification for: 'European or Other', of 0.02 percent a year Māori, of 0.39 percent a year Asian, of 0.16 percent a year Pacific, of 0.08 percent a year Because age-specific rates are applied, overall net IEM changes over time and will vary between areas. Low and high net IEM assumptions are chosen to represent plausible alternative IEM scenarios for each area and each ethnic group. Which projection should I use? Three alternative projections (designated low, medium, and high growth) were produced for each area and each ethnic group using different fertility (and paternity), mortality, migration, and inter-ethnic mobility assumptions. Users can make their own judgment as to which projections are most suitable for their purposes. At the time of release, the medium projection is considered to be suitable for assessing future population changes and is consistent with the median projection (50th percentile) of the National Ethnic Population Projections: 2018(base)–2043 (released 28 May 2021) and the medium projection of the Subnational Population Projections: 2018(base)–2048 (released 31 March 2021). Other percentiles or projections cannot be directly compared because projection assumptions may be incompatible. Low and high projections allow users to assess the impact on population size and structure resulting from lower growth and higher growth scenarios, respectively. The low projections use low fertility, low paternity, high mortality, low net migration, and low net inter-ethnic mobility for each area and each ethnic group. The high projections use high fertility, high paternity, low mortality, high net migration, and high net inter-ethnic mobility for each area and each ethnic group. These low and high projections are independent of the national ethnic population projections and subnational population projections as they represent plausible alternative scenarios for each area. en-NZ