How Stats NZ compiles the Consumers Price Index, what the basket actually contains, and how the CPI feeds into Reserve Bank policy decisions.
The Consumers Price Index is New Zealand's headline measure of inflation. Stats NZ compiles and publishes the CPI quarterly, and its methodology is publicly documented.
What the index tracks
The CPI tracks a basket of goods and services representative of New Zealand household spending. The basket is reweighted every three years based on the Household Economic Survey, so the measured mix evolves with how households actually spend.
How data gets collected
Price collectors gather around 100,000 observations across a quarter, covering groceries, housing, transport, recreation, and more. Stats NZ publishes the per-item definitions and sampling approach alongside each release.
Why it matters for monetary policy
The Reserve Bank targets 1–3% CPI inflation on average over the medium term, with a mid-point objective of 2%. Quarterly CPI releases directly feed the Monetary Policy Committee's deliberations.
What CPI doesn't measure
CPI measures prices consumers actually pay, not the cost of assets. Residential property prices, for instance, don't enter directly — the index includes housing as a shelter-services component (rents, rates, construction costs) but not capital gains on homes.
When it's released
Quarterly, around the third week of the month following each reference quarter, on Stats NZ's release calendar.
This article is for general information only and is not personalised financial advice. Seek advice from a licensed financial adviser (registered on the FSPR) for guidance specific to your situation.