One of the current priorities at Statistics New Zealand is to make as full use of administrative data as possible, especially if it can augment survey data. As part of that, tax data from Inland Revenue was linked to the Household Labour Force Survey run by Statistics New Zealand.
Once per year, the Household Labour Force Survey is augmented by the New Zealand Income Survey. The intention of linking tax data with the household survey is to see if the tax data could replace income information used in the household survey, in particular the New Zealand Income Survey supplement.
This presentation looks at the results of this linkage, including the assumptions and limitations in the data. We compare the high level results of the two original data sources to see if they are comparable in the first place, and then look at using the linked results to produce survey estimates to see how they compare to the original survey results.
We also look at the record level to see how correlated the survey answers are with the tax data.
Finally, we present a set of recommendations for how the tax data can be used for this, and other, surveys.