29 Apr 2019

Census 2018: Stats NZ sets September release for 'robust' data

2:46 pm on 29 April 2019

Stats NZ says it has plugged enough of the gaps in last year's census to be able to start releasing data from September, but some data - including iwi statistics - are too incomplete to be regarded as official statistics.

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Photo: 123RF

Using a methodology that combines 89 percent of real census data and 11 percent of other government administrative data, Stats NZ said it now had records for 4.7 million people in the dataset.

In a statement, government statistician Liz MacPherson said the data now met the quality criteria for population structure information, meaning it could be used for planning, population-based funding for DHBs, and electorate boundaries.

"This means Stats NZ will use 2018 Census data to update the official population estimates and projections that many organisations use for their planning," Ms MacPherson said.

Earlier this month, Ms MacPherson admitted that nearly one in seven people did not complete the census. The low response rate has delayed the data release twice.

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Government statistician Liz MacPherson. Photo: RNZ

"The release of data has been delayed twice because of the complex and careful work required to lift the quality of the census dataset," Ms MacPherson said.

She said she wanted to make it clear this dataset was reliable, robust, and based on maths, not guesswork.

"We've added real data about real people to the census dataset. The data are reliable government administrative records that we hold in trust on behalf of the nation.

"We are confident that we are including genuine information about people we are sure were in New Zealand on Census Day, to help us provide as complete a picture as we can."

While government records helped to fill in gaps, Stats NZ said it could not be used for all the census topics and as a result some data might not be released as official statistics.

"We will work through the implications of this with our customers as we confirm the data quality of each topic," Ms MacPherson said.

One of the datasets that won't be released as official statistics is counts of iwi, because of the level of missing iwi affiliation data, and the lack of alternative government data sources.

"I acknowledge this is a significant loss and we are not walking away from this situation. We are working in partnership with the Data Iwi Leaders Group, Māori interest organisations, iwi, and Māori to find real and relevant solutions to Māori data needs for Aotearoa," Ms MacPherson said.

Key dates for 2018 Census data:

  • Early May 2019 - technical seminars held in main centres and online
  • By July 2019 - findings from the independent review of the 2018 Census released
  • 23 September 2019 - first release of 2018 Census data (including resident population counts, census night population counts, number of general and Māori electorates, population counts needed to support the electorate boundaries, dwelling counts, census totals for some topics)
  • Stats NZ also expects to be able to start processing prioritised customised data requests from 23 September 2019.
  • December 2019 - Stats NZ will submit a business case for a 2023 Census
  • By March 2020 - Stats NZ will release the official census undercount and response rate in the 2018 Census Post-Enumeration Survey report
  • By mid-2020 - Stats NZ will complete the release of 2018 Census products and services
  • Mid-2020 onwards - demographic projections will be released progressively

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