National Population Estimates: June 2012 quarter

Data quality

Period-specific information
This section contains information that has changed since the last release.

General information
This section contains information that does not change between releases.

Period-specific information

National Population Estimates releases become annual

The last quarterly National Population Estimates release will be available in mid-November 2012 for the September quarter. From then on, National Population Estimates will become an annual information release. It will be published in mid-August each year, for the year ended June.

National population estimates data for March, September, and December will remain available in Infoshare, but information releases and media releases will not be produced for those quarters.

National Population Estimates – date and type of releases for 2012 and 2013 

Period covered

 Date of release

 Type of release

June 2012 quarter

 August 2012

 Full

September 2012 quarter

 November 2012

 Full

Year ended December 2012

 February 2013

 Table update only

Year ended March 2013

 May 2013

 Table update only

Year ended June 2013

 August 2013

 Full

Year ended September 2013

 November 2013

 Table update only

Removal of web page for national population estimates web tables

From August 2012, the page for national population estimates web tables will be removed from our website. The 'as at' and 'mean' national population estimates will be available in Infoshare, our free, online time series database. These estimates are available on Infoshare by sex and single-year of age, five-year age groups, broad age groups, and median age.

To access the population estimates data, select the following categories from the Infoshare homepage:

Subject category: Population
Group: Population Estimates

Upcoming changes to Population Estimates series in Infoshare

The DAE - Demography Age Estimates group will be removed from Infoshare in mid-August 2012, but its data will be available from the DPE - Population Estimates group. The 'as at' and 'mean' defacto population estimates are available in the DPE group as discontinued series. They are no longer being updated, but will continue to be available in Infoshare.

To access the discontinued series of population estimates data, select 'show discontinued' below the 'subject categories' heading.

To access the population estimates data, select the following categories from the Infoshare homepage:

Subject category: Population
Group: Population Estimates

General information

Base population

The estimated resident population at 30 June 2006 forms the base population for deriving post-censal population estimates.

The estimated resident population of New Zealand at 30 June 2006 is the 2006 census usually resident count from the 2006 Census (held on 7 March 2006), updated for:

  • residents 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 and 30 June 2006
  • reconciliation with demographic estimates at ages 0–4 years.

Quarterly national population estimates from September 2006 onwards were derived by updating the estimated resident population at 30 June 2006 for births, deaths, and net migration during the following period.

Accuracy of the data

Official national population estimates give the best available measure of how many people usually live in New Zealand. However, estimates are uncertain. Statistics NZ produces national population estimates using a component methodology, where the components of population change (births, deaths, and international migration) are used to update a base population. There is some uncertainty associated with component data, particularly when estimating international migration. Generally speaking, the uncertainty associated with population estimates increases as the estimates move further away from the base (starting point). Uncertainty also increases as population estimates are broken down by age and sex.

International migration estimates

International migration statistics are based on electronic arrival and departure records supplied to Statistics NZ for each international passenger. All arrivals and departures are processed so they can be allocated to one of three passenger types: overseas visitors, New Zealand-resident travellers, and permanent and long-term migrants. The net number of permanent and long-term migrants provides the estimate of international migration used in deriving the national population estimates.

Uncertainty arises due to changes in passenger intentions; a person may change their intentions after their arrival or departure, which may mean the recorded passenger type becomes incorrect. Statistics NZ does not revise published statistics to adjust for such changes. As a result, the uncertainty associated with population estimates increases as the time period between the reference date of the base population and the date of the estimate increases.

Birth and death estimates

There is some uncertainty associated with birth and death data. Birth and death registrations are used to estimate the number of births and deaths that occurred during each quarter. Not all births and deaths that occur in a quarter are registered by the end of the quarter, and this delay in registration is taken into account when estimating the number of births and deaths in the current quarter.

Determining data accuracy

It is not possible to verify the accuracy of current national population estimates, as no other independent or authoritative measure of the resident population exists. The periodic Census of Population and Dwellings remains the cornerstone of population statistics in New Zealand. Following the 2013 Census, it will be possible to derive updated estimates of the population, to assess the accuracy of estimates since 2006, and to revise estimates where necessary.

Provisional and final estimates

Provisional and final estimates are produced for the resident population each quarter. Provisional estimates are published in quarterly information and media releases. This is the first public release of population estimates. Estimates are released within six weeks of the end of the reference quarter. Final estimates are derived when an extra quarter of detailed births and deaths data is available, about five months after the end of the reference quarter. Changes between the provisional and final estimates are most apparent at the younger and older age groups, due to delayed registrations of births and deaths.

Birth estimates

Final estimates of births in a quarter are less accurate, as deaths are usually registered more quickly than births. Around 5 percent of births are not registered either in the quarter when the baby was born or in the subsequent quarter. Final quarterly estimates of births have a 95 percent confidence interval of ±500 (or about 3.5 percent, based on an average of 14,000 births per quarter).

Death estimates

The estimate of deaths that occurred in the reference quarter is taken as those deaths that were registered either in the reference quarter or in the subsequent quarter, and the number of people who died in the reference quarter. The provisional estimates of quarterly deaths have a 95 percent confidence interval of ±250 (or about 3.5 percent, based on an average of 7,000 deaths per quarter). Final estimates of deaths are very accurate as very few deaths (about 1 death in every 1,000) are registered later than one quarter after they occurred.

Population clock

Statistics NZ's online population clock gives a real-time approximation of the estimated resident population of New Zealand. The population clock uses the latest quarterly estimated resident population, and estimates of the expected number of births, deaths, and net migration for the coming quarter. The settings for each component (births, deaths, and net migration) are derived by converting the quarterly estimated totals into a 'per minute' figure, making allowance for the number of days per quarter.

2006-base population estimates extended

Statistics NZ planned to produce 2006-base post-censal estimates until mid-2012. Because the 2011 Census of Population and Dwellings was cancelled, 2006-base post-censal estimates will now be produced until mid-2014.

2013-base population estimates

The 2013 Census of Population and Dwellings will take place on Tuesday, 5 March 2013. The 2013 Census website provides information about the census.

Population estimates based on the 2013 Census will be released from August 2014. In addition, all population estimates after 30 June 2006 will be revised based on results from the 2013 Census. 

Rounding

All figures in this release were rounded independently. Estimates of the total population, natural increase, net migration, and broad age groups are rounded to the nearest 100. National population estimates of five-year age groups are rounded to the nearest 10.

All derived figures in this release were calculated using data of greater precision than that published.

More information

See more detailed information about population estimates and methods used to calculate them.

Liability

While care has been used in processing, analysing, and extracting data and information in this publication, Statistics NZ gives no warranty it is error-free and will not be liable for any loss or damage suffered by the use, directly or indirectly, of any information in this publication.

Timing of published data

Our information releases are delivered electronically by third parties. Delivery may be delayed by circumstances outside our control. Statistics NZ does not accept responsibility for any such delay.

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