Corrections to Household expenditure statistics

Corrections to Household expenditure statistics: Year ended June 2016 and Household income and housing-costs statistics: Year ended June 2017

13 April 2018

Household expenditure statistics: Year ended June 2016 and Household income and housing-costs statistics: Year ended June 2017 were both corrected on 13 April 2018.

Stats NZ has republished the data to correct an error. Household expenditure statistics: Year ended June 2016 was first published on 2 December 2016. Household income and housing-costs statistics: Year ended June 2017 was first published on 19 October 2017, and corrected on 8 December 2017.

See Household expenditure statistics: Year ended June 2016 and Household income and housing costs statistics: Year ended June 2017 for the corrected data.

Stats NZ is an open and transparent organisation and corrects errors as soon as practicable. We have rigorous processes to check data before publication.

We review any error to reduce and mitigate future risks. The lessons learned from this error will be used to guide future development of HES and other surveys. This is particularly important in light of Stats NZ’s future role in producing independent reports on measures of child poverty.

Stats NZ regrets the error and apologises for any inconvenience caused.

What is the impact on key Stats NZ statistics?

Prices

Household economic survey (HES) expenditure data for 2015/16 informed the 2017 consumers price index (CPI) review. Specifically, the data was used to calculate the relative importance (ie expenditure weights) of the majority of items in the basket of goods and services, as published in Consumers price index: December 2017 quarter on 25 January 2018.

Stats NZ has re-calculated CPI expenditure weights using corrected HES data. See Consumers price index review: 2017 for the updated expenditure weights.

Stats NZ has confirmed the updated expenditure weights do not affect the published ‘CPI all groups’ or group-level index numbers for the December 2017 quarter. However, there was an impact across a selected subgroup and class-level indexes. Stats NZ will not revise previously published data for the CPI or food price index (FPI).

Stats NZ will correct affected index numbers in the Food price index: March 2018 and Consumers price index: March 2018 quarter releases, set for publication on 16 and 19 April 2018, respectively.

The 2015/16 HES expenditure corrections will also impact the suite of household living-costs price indexes (HLPI). Stats NZ is undertaking work to determine the magnitude of this impact. The next HLPI release is set for publication on 3 May 2018.

National accounts

HES expenditure data is used to inform the measurement of household consumption expenditure (HCE) within the set of national accounts. The corrected 2015/16 HES expenditure data will impact HCE statistics from the 2014 March year onwards. This impact will be explored in this year’s update to annual benchmarks, set for publication in late 2018.

What is the impact on the wider data system?

HES income and housing-costs data underpins the Ministry of Social Development’s Household Incomes in New Zealand report. The most recent report uses 2015/16 HES data. The next report, planned for release in mid-2018, will use 2016/17 HES data.

How did the error occur?

The HES is a sample survey that uses several steps to rate up, or weight, the data from the sampled households to represent the population of New Zealand. The error that was discovered related to the first step of this process for the 2015/16 and 2016/17 HES datasets.

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