Quality Statement

Label
Total personal income - 2023 Census: Information by concept en-NZ
Definition

Total personal income received is the total before-tax income of a person in the 12 months ended 31 March 2023. The information is collected as income bands rather than in actual dollars.

Sources of personal income – Information by concept has further information on what was considered as income.

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Overall quality rating

High quality
Data quality processes section below has more detail on the rating.

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Priority level

Priority level 2
A priority level is assigned to all census concepts: priority 1, 2, or 3 (with 1 being highest and 3 being the lowest priority).
Total personal income is a priority 2 concept. Priority 2 concepts cover key subject populations that are important for policy development, evaluation, or monitoring. These concepts are given second priority in terms of quality, time, and resources across all phases of a census.

The census priority level for total personal income remains the same as 2018.

The 2023 Census: Final content report has more information on priority ratings for census concepts.

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Subject population

Census usually resident population count aged 15 years and over
‘Subject population’ means the people, families, households, or dwellings that the variable applies to.

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How this data is classified

Total personal income data is classified into the following categories:

Census Income bands V2.0.0 – level 1 of 1

Code Category Code Category
11 Loss 21 $40,001–$50,000
12 Zero income 22 $50,001–$60,000
13 $1–$10,000 23 $60,001–$70,000
15 $10,001–$15,000 24 $70,001–$100,000
16 $15,001– $20,000 25 $100,001–$150,000
17 $20,001– $25,000 26 $150,001–$200,000
18 $25,001–$30,000 27 $200,001 or more
19 $30,001–$35,000 99 Not stated
20 $35,001–$40,000
Total personal income uses a 1-level flat classification as presented in the table above.

The level 1 category 'Not stated' is a residual category. Follow the link above the table to examine the classification.

The 2023 Census classification for total personal income differs to the 2018 Census classification in the following ways:
  • 2018 Census’s lower bands (‘$1–$5,000’ and ‘$5,001–$10,000’) are replaced with ‘$1–$10,000’
  • an additional higher-level band is introduced (‘$150,001–$200,000’)
  • the top income band is changed from ‘$150,001 or more’ to ‘$200,001 or more’.

Standards and classifications has more information on what classifications are, how they are reviewed, where they are stored, and how to provide feedback on them.

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Question format

Total personal income data is collected from the individual form (question 37 paper form).

There were differences in question layout, and the way a person could respond between the modes of collection (online and paper forms).

On the online form:

  • respondents could tick as many options as required but it was not possible to mark both ‘no source of income’ and source(s) of income.

On the paper form:

  • respondents could also tick as many options as required but it was possible to mark both ‘no source of income’ and source(s) of income.

Data from the online forms may therefore be of higher overall quality than data from paper forms. However, processing checks and edits were in place to improve the quality of the paper form.

Stats NZ Store House has samples for both the individual and dwelling paper forms.

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Examples of how this data is used

Data-use outside Stats NZ:

  • combined with sources of personal income to give a better indication of the socio-economic status and wellbeing of individuals
  • to examine inequity in income across population groups including by ethnicity, gender, and age
  • for formulating social and economic policy, planning, research, and monitoring programmes
  • used to derive equivalised household income, which is used as an input for the New Zealand Index of Deprivation (NZDep).

Data-use by Stats NZ:

  • to stratify the sample for ongoing surveys such as the Household Economic Survey (HES) and Household Labour Force Survey (HLFS)
  • to derive family income, extended family income, and household income.
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Data sources

Alternative data sources were used for missing census responses and responses that could not be classified or did not provide the type of information asked for. The table below shows the distribution of data sources for total personal income data.

Data sources for total personal income data, as a percentage of census usually resident population count aged 15 years and over, 2023 Census
Source of total personal income data Percent
2023 Census response 82.5
Historical census 0.0
Admin data 16.5
Deterministic derivation 0.3
Statistical imputation 0.8
 CANCEIS(1) donor's response sourced from 2023 Census form 0.8
 CANCEIS donor's response sourced from admin data <0.1
 CANCEIS donor's response sourced from deterministic derivation <0.1
No information 0.0
Total 100.0
1. CANCEIS = imputation based on CANadian Census Edit and Imputation System.
Note: Due to rounding, individual figures may not always sum to the stated total(s) or score contributions.

The following admin data sources were used, in priority order of use:
  • Inland Revenue Department
  • Ministry of Social Development
  • Working for Families.

Inland Revenue collects income as actual dollar values, but these are output into the income bands classification as described in How this data is classified.

Deterministic derivation is used where a respondent indicated that they have no sources of income for the sources of income question, and did not respond to the total income question. A zero total income is automatically assumed for these respondents.

If a response could not be found using any of the above data sources or using deterministic derivation, then missing information was filled using statistical imputation.

Editing, sourcing, and imputing data in the 2023 Census describes how data quality is improved by editing, and how missing and residual responses are filled with alternative data sources (admin data and historical census responses) or statistical imputation. The paper also describes the use of CANCEIS (the CANadian Census Editing and Imputation System), which is used to perform imputation. This webpage also contains a spreadsheet that provides additional detail on the admin data sources.

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Missing and residual responses

Missing and residual responses represent data gaps where respondents either did not provide answers (missing responses) or provided answers that were not valid (residual responses).

Where possible, alternative data sources have been used to fill missing and residual responses in the 2023 and 2018 Censuses.

Percentage of ‘Not stated’ for the census usually resident population count aged 15 years and over:

  • 2023: 0.0 percent
  • 2018: 0.0 percent
  • 2013: 9.7 percent.

There were no other residual responses remaining in the data.

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Data quality processes

Overall quality rating: High
Data has been evaluated to assess whether it meets quality standards and is suitable for use.

Three quality metrics contribute to the overall quality rating:

  • data sources and coverage
  • consistency and coherence
  • accuracy of responses.

The lowest rated metric determines the overall quality rating.

Data quality assurance in the 2023 Census provides more information on the quality rating scale.

Data sources and coverage: High quality
The quality of all the data sources that contribute to the output for the variable were assessed. To calculate the data sources and coverage quality score for a variable, each data source is rated and multiplied by the proportion it contributes to the total output.

The rating for a valid census response is defined as 1.00. Ratings for other sources are the best estimates available of their quality relative to a census response. Each source that contributes to the output for that variable is then multiplied by the proportion it contributes to the total output. The total score then determines the metric rating according to the following range:

  • 0.98–1.00 = very high
  • 0.95–<0.98 = high
  • 0.90–<0.95 = moderate
  • 0.75–<0.90 = poor
  • <0.75 = very poor.

The high proportion of data received from 2023 Census forms, alongside the quality of alternative data sources, resulted in a score of 0.97, which is a quality rating of high.

Data sources and coverage rating calculation for total personal income data, census usually resident population count aged 15 years and over, 2023 Census
Source of total personal income data Rating Percent Score contribution
2023 Census response 1.00 82.45 0.82
Admin data 0.84 16.45 0.14
Deterministic derivation 1.00 0.30 <0.01
CANCEIS(1) nearest neighbour imputation 0.40 0.79 <0.01
No information 0.00 0.00 0.00
Total 100.00 0.97
1. CANCEIS = imputation based on CANadian Census Edit and Imputation System
Note: Due to rounding, individual figures may not always sum to stated total(s) or score contributions.

Consistency and coherence: High quality
Total personal income is consistent with expectations across nearly all consistency checks, with some minor variation from expectations or benchmarks that makes sense due to real-world change, incorporation of other sources of data, or a change in how the variable has been collected.

For total personal income, the variation can be explained through real-world change, such as strong wage inflation, low unemployment rate, and jobseeker support benefit increase. Personal income levels are expected to change over time.

Accuracy of responses: High quality
Total personal income data has only minor data quality issues. The quality of coding and responses within classification categories is high, any issues with the variable appear in a low number of cases (typically in the low hundreds).

Despite possible respondent errors such as under-reporting of government benefit received and recall bias, the accuracy of responses is high. The data quality process for total personal income included cross-variable checks for consistency within the dataset, including with sources of personal income. For example, missing responses to total income were assigned to ‘zero income’ if a respondent had selected ‘no sources of income’ on paper forms.

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Recommendations for use and further information

Total personal income data can be used in a comparable manner to the 2013 and 2018 Censuses.

When using the data, users should be aware that the classification for total personal income has been updated in the 2023 Census. Data users should be aware of the changes in classification when making time-series comparisons.

Care must also be taken when cross-tabulating census total personal income with sources of personal income:

  • people may obtain income from more than one source
  • the time reference periods are different for the two variables. Total personal income relates to 12 months ending on 31 March 2023, in line with the tax year, while sources of income collects information for the 12 months ending 7 March 2023 (census night).

Comparisons to other data sources
Although there are surveys and sources other than the census that collect total personal income data, data users are advised to familiarise themselves with the strengths and limitations of the sources before use.

The Household Labour Force Survey (HLFS) provides more regular information on income (on an annual basis), but depending on the type of analysis being undertaken, it may be more appropriate to use census data.

Data users should also be aware of the following differences between census data and the HLFS:

  • Census aims to account for the total personal income of all usual residents aged 15 years and over, while the HLFS is based upon a sample of the population.
  • Census includes more sources of income than the HLFS, which only collects wages and salaries, self-employment, and government transfers income. Examples of other sources of income in the census include interests, dividends, rent, other investments, and other sources of income, including support payments from people who do not live in the same household.
  • Census collects information on income earned to March of the census year whereas the HLFS collects weekly income data during the June quarter, and a person’s income could change over a year.
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Information by variables from previous censuses

To assess how this concept aligns with the variables from the previous census, use the links:

Contact our Information centre for further information about using this concept.



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Information

History

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Revision Date Responsibility Rationale
38 26/09/2024 10:00:58 AM