This report describes the sample design and sample selection for the New Zealand Health Survey. It is a technical report intended for statisticians looking to understand the detail of the sample design.
A key objective of the sample design is to improve sample sizes for Māori, Pacific and Asian ethnic groups over what would be achieved from a typical multi-stage area sampling design. To do this a dual frame approach is used, combining an area-based sample from New Zealand as a whole with a list-based sample of addresses from the electoral roll.
The sample design was reviewed ahead of the 2015/16 survey year. The most important changes from the design used in the first four years of the continuous New Zealand Health Survey (2011–2014) are as follows.
- The first stage of the sample selection now uses Statistics New Zealand’s household surveys frame primary sampling units (PSUs) rather than meshblocks.
- PSUs are selected using Statistics New Zealand’s coordinated selection facility to manage overlaps between various government household surveys.
- PSUs selected for the area component of the sample are used on two separate occasions in the same calendar year.