Purpose
This paper explains how the Stats NZ data updates policy is applied to the Household Income and Living Survey (HILS). This applies to all published outputs from HILS, including household income, housing costs, and child poverty statistics.
Data updates policy guides how Stats NZ manages updates to data, statistics, insights, and other information it releases.
Why Stats NZ updates outputs from the Household Income and Living Survey
The application and publication of updates to outputs from the Household Income and Living Survey (HILS) helps to ensure the accuracy and integrity of the dataset and is in keeping with statistical best practice.
To maintain the trust of users of the data, updates - and explanations for why they are done - need to be communicated transparently. The larger the updates, or the longer the timeframe to which they may apply, the greater the need to inform users of the pending updates before their publication.
A data update is a change to a previously released statistic. Stats NZ does this when:
- new or more timely information has become available (including updated administrative data, population estimates, and household living-costs price indexes)
- new methods or data sources are introduced
- existing methods or data sources are updated.
While this policy applies to all HILS-derived outputs, its application will vary according to the nature of the update.
Outputs from HILS
The social and economic welfare of New Zealanders is measured through income, expenditure, housing costs, net worth, and non-monetary measures. HILS income is the base component of each collection period. In three-year cycles, extensive additional questions related to expenditure and net worth are separately included alongside income.
Specifically, HILS provides annual information on:
- the distribution of household gross and disposable income
- the economic resources available to households after accounting for housing costs
- the distribution of non-monetary material wellbeing and hardship
- child poverty.
Every three years, HILS also provides information on:
- average weekly household expenditure
- itemised household expenditure (which supports weighting for the consumers price index)
- the distribution and composition of net worth (assets minus liabilities) of households in New Zealand.
Updates policy guidance
The application of the updates policy to HILS is documented below. In considering updates, we try to balance the user's need for consistency with diminishing returns on accuracy. Any decision regarding an update will consider its impact on published outputs and on users' expectations or actions.
If we have updated estimates from a previous cycle of HILS, the updated estimates will be published alongside the estimates for the current year and will be denoted with an R in the relevant tables and charts.
The Child Poverty Reduction Act 2018 stipulates that the original estimates should be used to monitor progress, with 2017/18 estimates used as fixed baseline figures.
Updates due to more timely information
The most recent year of HILS will always include the most up-to-date data available.
The decision on whether to update, and re-release, previous estimates will specifically take the child poverty reporting and monitoring framework into account and will be based on the magnitude of the change, along with maintaining the public's trust and confidence in the integrity of published statistics. The importance of preserving the time series is another crucial factor in any such decision.
Updates to any or all of the following three data sources will result in an update of previously published HILS outputs:
- administrative data
- population estimates
- household living-costs price indexes.
Administrative data is updated on a regular basis as more recent and more accurate data becomes available for the time period. Previous estimates will be re-run using this new data every year, and at a minimum the HILS outputs for the most recent year will be updated.
HILS outputs are updated annually to incorporate the most up-to-date population estimates, which mainly reflect changes to net migration. HILS outputs are also updated to the most up-to-date population benchmarks after each census.
Household living-costs price indexes (HLPIs) are used as an inflator to move the fixed-line child poverty measures and are reviewed every three years alongside the CPI review. Household spending patterns change over time as tastes, lifestyles, and incomes change, and as the range of goods and services available to households changes.
Updates due to methodological changes
Major conceptual or methodological changes tend to be irregular, but as they can affect time-series analyses, they should be announced in advance, where practical.
Depth of update
Deciding how far back to update outputs depends on several factors. At a minimum, the current and previous year of HILS will be updated to validate annual changes.
Update timeline
The type of update required will determine when an update is implemented.
Frequency of update |
Update |
Every year |
|
As required |
|
Net worth and expenditure updates
The three types of updates indicated above also apply to the measures of net worth and expenditure. Due to the three-yearly rotational basis of both outputs, the update timeline is restricted .
Frequency of update |
Update |
Every release (three years) |
|
As required |
|
Enquiries
Household financial statistics
[email protected]
