New Zealand Abridged Period Life Tables

Series

Title

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Alternate Title

Abridged Life Tables

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Rights

Statistics New Zealand

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Abstract

Abridged period life tables for the total New Zealand male and female populations provide an indication of the trends in life expectancy between the construction of complete period life tables.

Abridged life tables are available in February (provisional) and May (final) of each year.

In between census years, Statistics NZ produces abridged period life tables using mortality rates for three successive years centred on a non-census year. These abridged life tables are an interim indication of mortality and survival trends of the total population until complete period life tables are derived.

An abridged life table presents functions for five-year age groups rather than by single-year of age, although age 0 and 1–4 years are identified separately.

The complete period life tables are the most authoritative source on life expectancy in New Zealand. They are produced every five years for the total New Zealand, Māori and non-Māori, male and female populations by single-year of age.

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Purpose

Life tables use information about age-sex-specific mortality rates to determine patterns of survivorship and life expectancy. In addition, life tables also provide other indicators describing the mortality within a population during a given period of time:

death probabilities,
survival probabilities,
survivors at specific ages,
years of life lived.

Life tables are widely used for descriptive and analytical purposes in demography, public health, epidemiology, population geography, biology and many other branches of science. For example, life tables are widely used for the purpose of calculating premiums for life insurance and annuities.

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Universe

New Zealand Abridged period life table population ^en-NZ

Frequency

Annual

Main users of the data

Statistics New Zealand
Insurance and actuarial companies
Ministry of Health
Health planners
Social researchers

Significant events impacting this study series

1996 Population concept used in the calculation of mortality rates changed from 'de facto' to 'resident'.

The population concept used for population estimates and projections changed from de facto to resident. The de facto population includes all persons in New Zealand at a given time. It includes overseas visitors, but excludes residents temporarily overseas and net census undercount.

The estimated resident population includes the estimated net census undercount and the estimated number of residents temporarily absent overseas, but does not include overseas visitors.

Resident population estimates do not show the quarterly fluctuations that de facto estimates are subject to because of seasonal changes in the numbers of overseas visitors temporarily in New Zealand, and changes in the numbers of New Zealand residents temporarily out of New Zealand.

Usage and limitations of the data

Most life tables are period life tables which commence with a hypothetical group of newborn babies, and assume that they experience the observed mortality rates of a given period throughout their life. The derived life expectancies give an indication of the average longevity of the population but do not necessarily reflect the longevity of an individual.

For most ages above 90 years, death rates of the total New Zealand population have been modelled on the mortality trends of other countries such as Australia, Canada, Japan, United Kingdom and United States. At the older ages it is assumed that the rate of change in probability of dying within a year(qx) decreases linearly with increasing age. For the Māori and non-Māori populations, death rates have also been modelled at ages in the early 80s and late 80s, respectively

Deaths numerator

The period life tables were compiled from deaths registered, rather than deaths occurring, in each respective three-year period. Most death statistics refer to registrations rather than occurrences for a given time period, because there is generally a time lag between when the death occurred and when it is registered. Hence, the number of death registrations can be confirmed before the number of death occurrences for a given time period. For periods of a year or more, the difference between registrations and occurrences is generally small, so death statistics referring to registrations are suitable for most purposes.