Families and households: extended family type (information about this variable and its quality)

Description

An extended family is a group of related people who usually reside together:

  • either as a family nucleus with one or more other related people, or
  • as two or more related family nuclei, with or without other related people.

Included are people who were absent on census night but who usually live in a particular dwelling and are members of an extended family in that dwelling, as long as they were reported as being absent by the reference person on the dwelling form or the household

Statistics

Representation

Variable Details

Other Variable Information

Following a detailed investigation into potential quality concerns the quality rating of this variable has been changed from very poor quality to poor quality.

Families and households in the 2018 Census: Data sources, family coding, and data quality has detailed information on the quality assessment for these variables and some changes in our methodology.

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).

Extended family type 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 extended family type remains the same as 2013.

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

Overall quality rating for 2018 Census

Poor quality

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

Subject population

Extended families in occupied private dwellings

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

How this data is classified

New Zealand Standard Classification of Extended Families V1.0.0

Extended family type is a hierarchical classification with three levels. Census only uses the first level of the classification. The criteria used to place an extended family into the first level of the classification is the number of generations present, and if two are present, whether they are adjacent or not. If two adjacent generations are present, the family is classified as a two-generation extended family. If two non-adjacent generations are present, the family is classified as a three- or more generation extended family.

1 One-generation extended family

2 Two-generation extended family

3 Three- or more generation extended family

9 Extended family not classifiable

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

Question format

Extended family type is derived from information about all the people who usually live in the household: residents who are present on census night and residents who are absent on census night (absentees). The following variables are used to determine relationships between the usual residents of the household:

  • Relationship to reference person
  • Absentee relationship to reference person
  • Living arrangements

For online forms the household set-up form asks for residents present on census night, any absentees, and the relationship of each resident to the reference person. Living arrangements is asked on the individual form.

On paper forms the dwelling form asks for residents present on census night and their relationship to reference person (question 17). Any absentees are listed on the dwelling form with absentee relationship to reference person (question 20). Living arrangements is asked on the individual form (question 17).

Both forms collect further information about absentees (usual residents who are absent on census night) regarding whether they are in New Zealand or overseas, and whether they are away for less than 12 months or 12 months or more. Absentees away from New Zealand for 12 months or more are not included as usual residents of the household.

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

How this data is used

Outside Stats NZ

  • By central government agencies, local authorities, private organisations, and researchers in the formulation of social policy, for planning and monitoring programmes, and for research purposes.

Within Stats NZ

  • To derive household and family projections.

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 administrative data from the Integrated Data Infrastructure (IDI).

The table below shows the breakdown of the various data sources used to place people in households (used to derive extended family type).

2018 sources used to derive extended family type –
households in occupied private dwellings
Source Percent
Response from 2018 Census 93.4 percent
Response from 2018 Census and administrative data* 0.8 percent
Administrative data 2.2 percent
No information 3.6 percent
Total 100 percent
Due to rounding, individual figures may not always sum to the stated total(s)
*Households where some members were enumerated from 2018 Census forms, and
others from administrative data.
 

‘No information’ in the table above is the percentage of non-responding households. A household is classified as non-responding when we have evidence that a private dwelling was occupied on census night but we did not receive a response and we were unable to identify usual residents of the household in administrative data. The usual residents of these non-responding dwellings may have been present in administrative data, but we did not have enough evidence to place them into a specific household. In these cases, individuals were placed into a meshblock instead. Non-responding households were coded to ‘household composition unidentifiable’.

Administrative data sources

We enumerated individuals from the range of sources available in the Integrated Data Infrastructure (IDI).

The potential for linked administrative data to provide household and family information provides information on sources of administrative data used.

Overview of statistical methods for adding admin records to the 2018 Census dataset provides information on the linking of census responses to the IDI and has more information on the timeliness of administrative data.

Please note that when examining extended family type data for specific population groups within the subject population, the percentage that is from administrative data may differ from that for the overall subject population.

Missing and residual responses

Extended family type does not have a non-response or ‘not stated’ category. No information’ in the data sources table is the percentage of households we were unable to determine household composition for, and therefore were unable to identify if the household contains an extended family.

Percentage of ‘extended family type not classifiable’ for extended families in occupied private dwellings:

  • 2018: 0.1 percent
  • 2013: 0.1 percent
  • 2006: 0.1 percent.

Data quality processes

Overall quality rating: Poor 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: 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.

The data sources and coverage quality rating for extended family type is the same as for household composition, as extended family type is derived from household composition. For household composition, the data source ratings represent the likelihood that the correct people are placed within the correct household.

The proportions of data from 2018 Census and administrative data contributed to the score of 0.96, determining the high quality rating.

Quality rating calculation table for the sources used to derive family type – 2018 households in occupied private dwellings
Source Rating Percent of total Score contribution
2018 Census form 1.00 93.39 0.93
2018 Census and admin data* 1.00 0.82 0.01
Admin data 0.64 2.16 0.01
No Information 0.00 3.63 0.00
Total 100.00 0.96
Due to rounding, individual figures may not always sum to the stated total(s) or score contributions.
*Households where some members were enumerated from 2018 Census forms, and others from administrative data.
     

Consistency and coherence: High quality

Extended family type 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.

Data quality: Poor quality

Data quality was determined by assessing how many records in the subject population had been flagged as having a potential error. An error flag indicates a household may have been miscoded or may have a missing person, and therefore may have incorrect characteristics.

Family and household variables with error flag rates below 6 percent were given a data quality rating of moderate, those with between 6 percent and 9.99 percent were given a rating of poor, while variables with error flag rates of 10 percent or greater were given a rating of very poor.

The extended families in occupied private dwellings subject population had between 6 and 9.99 percent error rate, determining the poor quality rating.

Families and households in the 2018 Census: Data sources, family coding, and data quality has more information on error flags.

Quality issues to note

  • Extended families are more likely to have a larger number of household members. Households with six or more usual residents, and households with more than one family have a higher error rate than smaller households.

Quality ratings of related variables

The table below summarises the quality ratings of variables related to extended family type.

Quality ratings of related variables        
Variable Data sources and coverage Consistency and coherence Data quality Overall quality rating
Count of extended families High Very high Moderate Moderate
Count of people in extended families Moderate Moderate Moderate Moderate

Quality issues to note for related variables:

Recommendations for use and further information

Extended family type is poor quality due to the relatively high error rate. However, this data can still be used with caution.

When using this data you should be aware that:

Contact our Information Centre for further information about using this variable

Revision Information

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