Quality Statement
Main means of travel to work is the usual method which an employed person aged 15 years and over used to travel the longest distance to their place of employment (for example, by bicycle, public bus, walking, or driving).
‘Usual’ is the type of transport used most often – for example, the one used for the greatest number of days each week, month, or year. If there are two (or more) forms of transport used equally as often, the most recent form of transport was recorded.
‘Main’ is the type of transport used for the component of the journey that covers the longest distance.
Moderate quality
Data quality processes section below has more detail on the rating.
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).
Main means of travel to work 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 main means of travel to work remains the same as 2018.
The 2023 Census: Final content report has more information on priority ratings for census concepts.
Employed census usually resident population count aged 15 years and over
‘Subject population’ means the people, families, households, or dwellings that the variable applies to.
Main means of travel to work is classified into the following categories:
Census main means of travel to work V1.0.0 – level 1 of 2
Code | Category |
---|---|
001 | Work at home |
002 | Did not go to work today |
003 | Drive a private car, truck or van |
004 | Drive a company car, truck or van |
005 | Passenger in a car, truck, van or company bus |
006 | Public bus |
007 | Train |
009 | Bicycle |
010 | Walk or jog |
012 | Ferry |
016 | Other |
999 | Not elsewhere included |
Main means of travel to work uses a 2-level hierarchical classification with level 1 presented in the table above. The level 1 residual category ‘Not elsewhere included’ contains the residual categories ‘Response unidentifiable’ and ‘Not stated’. Follow the link above the table to examine the classification in more detail.
The 2023 Census classification for main means of travel to work is consistent with that used in the 2018 Census.
Standards and classifications has information on what classifications are, how they are reviewed, where they are stored, and how to provide feedback on them.
Main means of travel to work data is collected from the individual form (question 47 paper form). Respondents are directed to answer for the job they worked the most hours in per week. The question states that if the respondent doesn’t have a usual travel method, then they should select the one they used most recently.
‘Work at home’ was coded through responses to the workplace address question (question 46 paper form).
There were differences in the way a person could respond between the modes of collection (online and paper forms).
On the online form:
- this question was only presented to the in-scope population
- multi-response was not possible - if a respondent selected more than one box, the first response was deselected.
On the paper form:
- it was possible for respondents who were not part of the usually resident population or unemployed to respond to the main means of travel to work question
- multiple responses for this question were possible, which were resolved through edits.
Data from 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 data.
Stats NZ Store House has samples for both the individual and dwelling paper forms.
Data-use outside Stats NZ:
- in conjunction with other transport and location data from the census (for example, travel to education or workplace address) to plan and manage transport and other infrastructure, for example, by transport planners in large cities where there are congestion issues
- to measure the number of people working from home
- for monitoring investment in certain travel modes, such as investments to support walking and cycling
- to focus targeted initiatives aimed at encouraging more people to use public transport.
Data-use by Stats NZ:
- in conjunction with workplace address to measure commuting flows of the employed population.
Alternative data sources were used for missing and residual 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 main means of travel to work data.
Data sources for main means of travel to work data, as a percentage of employed census usually resident population count aged 15 years and over, 2023 Census | ||
---|---|---|
Source of main means of travel to work data | Percent | |
2023 Census response | 83.8 | |
Historical census | 0.0 | |
Admin data | 0.2 | |
Deterministic derivation | <0.1 | |
Statistical imputation | 15.9 | |
CANCEIS(1) donor’s response sourced from 2023 Census form | 15.9 | |
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. |
Statistical imputation via CANCEIS where the donor’s response is sourced from the 2023 Census form is the main alternative data source for main means of travel to work data.
There are a small proportion of records with a data source of admin data or deterministic derivation. This approach was used when a respondent had an alternatively sourced workplace address which was the same as their usual residence address. In this case they were coded to work at home for this question. The workplace address data source was copied to the travel to work data source and was either deterministically derived from a census response (if the workplace address was sourced from the business name) or admin data.
If the addresses were different, the indicator was coded to ‘work away from home’ and main means of travel to work was coded according to their census response or CANCEIS imputed if necessary.
Editing, data sources, and imputation 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.
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 employed census usually resident population count aged 15 years and over:
- 2023: 0.0 percent
- 2018: 0.0 percent
- 2013: 2.5 percent
For output purposes, the residual category responses are grouped with ‘Not stated’ and are classified as ‘Not elsewhere included’.
Percentage of ‘Not elsewhere included’ for the employed census usually resident population count aged 15 years and over:
- 2023: 0.0 percent
- 2018: 0.0 percent
- 2013: 3.7 percent
Overall quality rating: Moderate
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: Moderate 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 proportion of data from received forms and statistical imputation contributed to the score of 0.94, determining the moderate quality rating.
Data sources and coverage rating calculation for main means of travel to work data, employed census usually resident population count aged 15 years and over, 2023 Census | |||
---|---|---|---|
Source of main means of travel to work data | Rating | Percent | Score contribution |
2023 Census response | 1.00 | 83.79 | 0.84 |
Admin data | 0.70 | 0.25 | <0.01 |
Deterministic derivation | 1.00 | 0.02 | <0.01 |
CANCEIS(1) nearest neighbour imputation | 0.60 | 15.94 | 0.10 |
No information | 0.00 | 0.00 | 0.00 |
Total | 100.00 | 0.94 | |
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
Main means of travel to work data is consistent with expectations across nearly all consistency checks, with some minor variation from expectations or benchmarks which makes sense due to real-world change, incorporation of other sources of data, or a change in how the variable has been collected.
The increase in the ‘work at home’ category is attributable to changes in working arrangements post the COVID-19 pandemic. Changes in trends in main means of travel to work were consistent with trends in main means of travel to education, indicating real-world change.
Accuracy of responses: High quality
Main means of travel to work 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).
Any differences between modes and geography can be explained by real world differences such as work type. The introduction of manual scanning repair in 2023 improved the quality of scanned forms as less accidental multi-response was recorded (for example, where someone ticked a box, crossed it out and ticked another). However, there will be respondents who do have more than one means of travel to work and have missed that the question is asking for one main way they travelled, and provide multiple responses to the question. As such, the proportion of paper forms that have had the multi-response edit for main means of travel to work applied is similar to 2018, whereas for other variables it has decreased with the introduction of scanning repair.
Main means of travel to work data can be used in a comparable way to 2018 and 2013.
When using this data, users should be aware that:
- Caution is advised when using this variable and when cross-tabulating with the workplace address variable at lower level geographies as there will be variability in the percentage of imputation for a given area. This means some small geographic areas will have poorer quality data than the overall quality rating.
- When comparing 2023 and 2018 census data with 2013 or prior censuses users should be aware that there has been a conceptual change to the question. In the 2013 and prior censuses, respondents were asked about their travel on census day, rather than the main way they usually travel to work. This means the historical classifications included a category for ‘Did not go to work today’. There were also some changes in the methods of transport collected on the forms. Due to these changes, it is recommended to use proportions rather than counts for timeseries comparisons to 2013 and prior censuses and for earlier census periods to only include respondents who travelled to work on census day.
- There are a small number of people that report using transport modes that are not available in the region of their usual residence address. The categories of 'Ferry' and 'Train' are very uncommon and heavily limited in the areas where they are available. These categories should be used with care unless looking at the Auckland, Wellington, or Canterbury regions and specifically in the areas where it is available within these regions.
Comparisons to other data sources
Although surveys and sources other than the census collect travel data, data users are advised to familiarise themselves with the strengths and limitations of the sources before use.
Census aims to be a national count of the main means of travel to work for all employed individuals aged 15 years and over. The Household Travel Survey run by the Ministry of Transport is the closest comparable source, however this survey captures all travel for a household within a 2-day period, collects multi-modal travel, and has a small sample size (around 2,000 households are surveyed annually).
To assess how this concept aligns with the variables from the previous census, use the links below:
- Main means of travel to work – 2018 Information by variable
- Main means of travel to work – 2013 Information by variable
Contact our Information centre for further information about using this concept.