Quality information for highest qualification in the 2018 iwi affiliation estimated counts dataset

Quality rating: Moderate to poor quality

For many purposes, the 2018 iwi estimates provide a more relevant and up-to-date picture than continued use of 2013 Census iwi data. These iwi estimates are not official 2018 Census counts and the quality ranges from moderate to poor depending on how the data is used. It is difficult to understand changes occurring for an iwi over time for the population count as well as across characteristics due to differences between the 2018 and 2013 Censuses:

• Counts for the overall Māori descent population are substantially higher in 2018, reflecting improvements in the quality of Māori descent population counts in the 2018 Census as well as natural population change (births, deaths, migration). Māori descent – Information by Variable 2018 provides more information on the changes in the Māori descent population.

• Changes were made to the collection of iwi data in the 2018 Census, for example changes to the online form, and in 2017 there was a substantial review of the iwi classification with 32 iwi being added to the classification.

• There may also be a combination of real-world and methodological change at the characteristic level.

Producing estimates for the characteristics of an iwi is lower quality than we would expect from a census due to the high level of non-response. This is particularly the case when estimating the size of very small groups (e.g. <100).

###Data sources for highest qualification in the 2018 iwi affiliation estimated counts dataset

As highest qualification is derived from two input variables (highest secondary school qualification and post-school qualification level), we have combined the categories ‘2013 Census data’ and ‘Administrative’ data into a single column which indicates if either one or both of the input variables were sourced from these alternative sources. This is displayed in the table below.

Further information on the 2018 iwi affiliation estimated counts dataset

2018 Iwi affiliation estimated counts – DataInfo+ provides detailed information on the quality of the 2018 Iwi Affiliation Estimated Counts dataset.

Methodology for the 2018 iwi affiliation estimated counts provides detailed methodology for the 2018 iwi affiliation estimated counts.

Strengths and limitations of 2018 iwi affiliation estimated counts provides high level guidance on using the 2018 Iwi Affiliation Estimates Counts.

Iwi affiliation (estimated counts): 2018 data sources and quality by iwi provides estimated counts quality information by iwi.

Further information on the highest qualification variable in the 2018 Census

Highest qualification – Information by Variable (2018 Census) provides a more detailed summary of the differences between the 2013 Census and 2018 Census questionnaires and the quality of the 2018 Census highest qualification data. However, the quality rating provided in the 2018 document does not apply to the highest qualification variable in the iwi estimated counts dataset.

2018 Census External Data Quality Panel: Initial report provides quality information on highest qualification and other key demographic variables.

Stats NZ Store House provides samples for both the 2018 individual and dwelling census paper forms.