Birthplace (information about this variable and its quality)


Birthplace refers to the country where a person was born and uses the name of the country at the time of the census. Country is the current, short or official name of a country, dependency, or other area of particular geopolitical interest. The term is defined to include:

  • independent countries recognised by the New Zealand Government
  • units that are recognised geographic areas
  • administrative subdivisions of the United Kingdom
  • overseas dependencies, or external territories of independent countries.



Variable Details

Other Variable Information

Priority level

Priority level 2

We assign a priority level to all census variables: Priority 1, 2, or 3 (with 1 being highest and 3 being the lowest priority).

Birthplace is a priority 2 variable. Priority 2 variables cover key subject populations that are important for policy development, evaluation, or monitoring. These variables are given second priority in terms of quality, time, and resources across all phases of a census.

The census priority level for birthplace remains the same as 2013.

Quality Management Strategy and the Information by variable for birthplace (2013) have more information on the priority rating.

Overall quality rating for 2018 Census

High quality

Data quality processes section below has more detail on the rating for this variable.

The External Data Quality Panel has provided an independent assessment of the quality of this variable and has rated it as high quality. 2018 Census External Data Quality Panel: Assessment of Variables and Final report of the 2018 Census External Data Quality Panel have more information.

Subject population

Census night population

Birthplace is also output for the census usually resident population. Analyses of data sources and quality for birthplace are done using the usually resident population. This was the same process as in the 2013 Census. The 2018 dataset and Data quality processes sections below have more information.

‘Subject population’ means the people, families, households, or dwellings to whom the variable applies.

How this data is classified

Census birthplaceV1.0.0

Birthplace is a hierarchical classification with three levels. Level 1 contains 10 major country groups (including supplementary codes), level 2 contains 35 minor country groups (including residual categories), and level 3 contains 276 countries and residual categories.

Countries are grouped according to geographic proximity. They are then grouped into progressively broader geographic areas based on their similarity in terms of social, cultural, economic, and political characteristics. Level 1 of the classification is the broadest geographic area.

The top level (level 1, major country groups) are:

0 Supplementary Codes

1 Oceania and Antarctica

2 North-West Europe

3 Southern and Eastern Europe

4 North Africa and the Middle East

5 South-East Asia

6 North-East Asia

7 Southern and Central Asia

8 The Americas

9 Sub-Saharan Africa

An example of the classification structure is:

  • Major Group 1 Oceania and Antarctica
  • Minor Group 12 New Zealand
  • Country 1201 New Zealand (includes the Ross Dependency)

Supplementary codes include residual categories such as ‘not stated’ and ‘inadequately described’. ‘At sea’ is included in the supplementary codes but is defined as a valid response.

Birthplace is usually output as a mixture of the most common responses of country and high-level groupings of countries with similarities, such as:

  • New Zealand
  • Australia
  • Pacific Islands
  • United Kingdom and Ireland
  • Europe (excluding United Kingdom and Ireland)
  • North America
  • Asia
  • Middle East and Africa
  • Other

Explanatory note

Although there have been no conceptual changes to this variable, there have been minor changes to the classification of this variable from the 2013 Census to review changes in official country names. This includes:

  • Burma (Myanmar) has been changed to Myanmar
  • Cape Verde has been changed to Cabo Verde
  • South Sudan has been added as a new country.

The Standards and Classifications page provides background information on classifications and standards.

Question format

Birthplace is collected on the individual form (question 8 on the paper form).

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

There has been a change to the question wording since 2013. In 2013 respondents who selected ‘other’ were instructed to print the present name of their country of birth. For 2018, the word ‘present’ was removed from both the online and paper forms.

There were differences in question format between the modes of collection (online and paper forms):

  • on the online individual form, respondents were asked to tick either New Zealand or overseas. If they ticked overseas, a text box was presented for respondents to write their birthplace.
  • on the paper form, tick boxes were provided for New Zealand, Australia, England, China, India, South Africa, Samoa, Cook Islands, and other. Respondents who selected other were instructed to print their country of birth in a text box.

There were also differences in the way a person could respond between the modes of collection (paper and online form).

On the online individual form:

  • as-you-type functionality helped respondents provide valid responses
  • respondents were only able to provide one country of birth.

On the paper individual and dwelling forms:

  • responses outside the valid range were possible
  • multiple responses to the birthplace question were possible. These responses were coded to ‘response unidentifiable’.

Data from the online forms may therefore be of higher overall quality than data from paper forms.

How this data is used

Outside Stats NZ

  • Data on birthplace and years since arrival in New Zealand is used to develop, monitor and evaluate settlement programmes for immigrants, and analyse the socioeconomic status of immigrants.
  • Birthplace is used to monitor employment and immigration policies and to plan the delivery of health, education and other social services to migrant groups.
  • Birthplace data is essential for analysing differences in education, employment, income and social situations of overseas-born New Zealanders compared to those born in this country.

Within Stats NZ

  • Used to provide information on the total size and characteristics of the overseas-born population in New Zealand at census time, and the proportions from each country.

2018 data sources

We used alternative data sources for missing census responses and responses that could not be classified or did not provide the type of information asked for. Where possible, we used responses from the 2013 Census, administrative data from the Integrated Data Infrastructure (IDI), or imputation.

The table below shows the breakdown of the various data sources used for this variable.

2018 country of birth – census usually resident population
Source Percent
Response from 2018 Census 83.8 percent
2013 Census data 8.6 percent
Administrative data 6.4 percent
Statistical imputation 0.0 percent
No information 1.2 percent
Total 100 percent
Due to rounding, individual figures may not always sum to the stated total(s)  

The ‘no information’ percentage is where we were not able to source country of birth data for a person in the subject population.

Administrative data sources

Data from the following administrative sources was used:

  • Births register, Department of Internal Affairs
  • Migration data, Ministry of Business, Innovation and Employment.

Potential for admin data to provide country of birth and years since arrival in New Zealand has more information.

Please note that when examining birthplace data for specific population groups within the subject population, the percentage that is from 2013 Census and administrative data may differ from that for the overall subject population.

Missing and residual responses

‘No information’ in the data sources table is the percentage of the subject population coded to ‘not stated’. In previous censuses, non-response was the percentage of the subject population coded to ‘not stated.’

In 2018, the percentage of ‘not stated’ is lower than previous censuses due to the use of the additional data sources described above.

Percentage of ‘not stated’ for the census usually resident population:

  • 2018: 1.2 percent
  • 2013: 5.9 percent
  • 2006: 4.5 percent.

Responses that could not be classified or did not provide the type of information asked for, such as Inadequately Described remain in the data, where we have been unable to find information from another source. In the data sources table, these residuals are included in the ‘Response from 2018 Census’ percentage.

For output purposes, these residual category responses are grouped with ‘not stated’ and are classified as ‘not elsewhere included’. Due to the small proportion of inadequately described responses, the percentage of ‘not elsewhere included’ matches that of ‘not stated’ to 1 decimal place.

Percentage of ‘not elsewhere included’ for the census usually resident population:

  • 2018: 1.2 percent
  • 2013: 6.1 percent
  • 2006: 4.7 percent.

2013 Census data user guide provides more information about non-response in the 2013 Census.

Data quality processes

Overall quality rating: High quality

Data was evaluated to assess whether it meets quality standards and is suitable for use.

Three quality metrics contributed to the overall quality rating:

  • data sources and coverage
  • consistency and coherence
  • data quality.

The lowest rated metric determines the overall quality rating.

Data quality assurance for 2018 Census provides more information on the quality rating scale.

Data sources and coverage: Very high quality

We have assessed the quality of all the data sources that contribute to the output for the variable. To calculate a 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:

  • 98–100 = very high
  • 95–<98 = high
  • 90–<95 = moderate
  • 75–<90 = poor
  • <75 = very poor.

2013 Census responses and admin data were highly comparable to 2018 Census responses. The proportions of these high quality data sources along with the low proportion of ‘no information’ contributed to the score of 0.98, determining the very high quality rating

Quality rating calculation table for the sources of birthplace data – 2018 census usually resident population
Source Rating Percent of total Score contribution
2018 Census form 1.00 83.78 0.84
2013 Census 0.99 8.55 0.08
Admin data 0.92 6.44 0.06
No Information 0.00 1.22 0.00
Total 100.00 0.98
Due to rounding, individual figures may not always sum to the stated total(s) or score contributions.      

Consistency and coherence: High quality

Birthplace data 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.

Quality issues to note:

  • while there are some variations from 2013 and 2006 Census data, this can be explained by better coding (as-you-type online functionality), and the use of high-quality data to replace most missing and residual responses, and respondent error
  • when comparing time series for birthplace categories, we recommend comparing change in each category by proportion of total stated excluding residuals, due to the decrease in missing and residual responses in 2018 compared to previous censuses.

Data quality: High quality

The data quality checks for birthplace included edits for consistency within the dataset and cross-tabulations to the regional council level of geography.

Birthplace data has only minor data quality issues. The quality of coding and responses within classification categories is high. Any impact of other data sources used is minor. Any issues with the variable appear in a low number of cases (typically in the low hundreds).

Quality issues to note:

  • in some cases on the paper form, respondents provided regions (for example, United Kingdom) instead of countries (for example, England, Northern Ireland). It was not possible to code these to the lowest level of the classification (for example a response of ‘United Kingdom’ was coded to ‘United Kingdom not further defined’, at level 3 of the classification). As-you-type functionality prevented this issue on online forms by providing a drop-down list of countries to choose from when respondents typed in a region.

Recommendations for use and further information

We recommend that the use of this data can be similar to its use in 2013.

However, when using this data you should be aware that:

  • data has been assessed to be consistent at the regional council level of geography. Some variation is possible at geographies below this level.
  • where respondents provided a country that no longer exists, these were coded to level 2 of the classification correctly but specified as ‘not further defined’ at level 3 (in cases where the current name of the country is not obvious, or the prior country is now multiple countries).
  • all analyses for this variable are based on the usually resident subject population. Some caution should be taken when using the census night subject population as overseas visitors in the census night subject population had more missing data for this variable.

Comparisons with other data sources

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

Key considerations when comparing birthplace information from the 2018 Census with other sources include:

  • census is a key source of information on birthplace for small areas and small populations. Many other sources do not provide detail at this level.
  • census aims to be a national count of all individuals in a population while other sources such as the Household Labour Force Survey and General Social Survey measuring this variable are only based upon a sample of the population.

Contact our Information Centre for further information about using this variable.

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