Projected population change in Porirua City, New Zealand

Medium projection: Assuming medium fertility, medium mortality, and medium net migration.
High projection: Assuming high fertility, low mortality, and high net migration.
Low projection: Assuming low fertility, high mortality, and low net migration.

Natural increase: live births minus deaths
Net migration: Long-term arrivals to the area minus long-term departures from the area. This includes migration within New Zealand

This dataset represents the latest update available as at September 2023.
Note: Net migration in the year ending June 2023 was much higher than the median net migration assumption used in the updated projections.

The projections are not predictions. The projections are designed to meet both short-term and long-term planning needs, but are not designed to be exact forecasts or to project specific annual variation. These projections are based on assumptions made about future fertility, mortality, migration, and inter-ethnic mobility patterns of the population. Although the assumptions are carefully formulated to represent future trends, they are subject to uncertainty. Therefore, the projections and associated probability intervals should be used as guidelines and an indication of the overall trend, rather than as exact forecasts.

Data is displayed at URL provided. To create this dataset, all variables were selected.

These projections have as a base the estimated resident population of each area at 30 June 2018. This population was based on the census usually resident population count of each area at 6 March 2018 and adjusted for:
a. net census undercount
b. residents temporarily overseas on census night
c. births, deaths, and net migration between census night (6 March 2018) and 30 June 2018
d. reconciliation with demographic estimates at ages 0–14 years.
The estimated and projected resident population is not directly comparable with the census usually resident population because of these adjustments.

Three alternative projections (designated low, medium, and high) have been produced for each area using different fertility, mortality, and migration assumptions. At the time of release, the medium projection is considered the most suitable for assessing future population change.
The 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 projection uses low fertility, high mortality, and low net migration for each area. The high projection uses high fertility, low mortality, and high net migration for each area. The low and high projections are independent of the national population projections as they represent plausible alternative scenarios for each area.