Open data, plainly explained

Where the data comes from

Indicators are drawn from public sources: Statistics New Zealand (CPI, unemployment, wages, and median household income), the Reserve Bank of New Zealand (the Official Cash Rate and several other rates, currently via a manually-entered, audited fallback while automated access is pending), MBIE (fuel demand and imports, market rent, and pump prices/crude oil/the exchange rate, the latter parsed exactly from a manually-downloaded file while automated access to it is also blocked), Employment New Zealand (the adult minimum wage), the Living Wage Movement Aotearoa New Zealand (the voluntary Living Wage rate), and the Ministry for Cities, Environment, Regions and Transport (median house price). Each indicator stores its own source name, URL, and update timestamp.

How charts are calculated

Indexed charts rebase every series to 100 at the start of the chosen baseline year, so very different measures (cents per litre, index points, dollars) can be compared on one axis. “% change since 2020” is always measured from the first observation of 2020 to the latest observation.

Live data vs. sample data: read this

Most indicators on this site are now live: CPI, annual inflation, unemployment, wages and wage inflation, median rent, fuel demand and imports, median household income and median house price are all fetched directly from their official sources and re-validated on every ingestion run. The Official Cash Rate and several other RBNZ rates are verified too, through a manually-entered, audited fallback rather than a fully automated feed - and pump prices, crude oil and the NZD/USD exchange rate are live the same way, parsed exactly from MBIE's own published file rather than typed in by hand. The adult minimum wage is live too, transcribed from Employment New Zealand's own published rate history, and the Living Wage is live from the Living Wage Movement's published rate, though currently only one point deep since no historical file exists for it. A remaining set of indicators are still sample data or not yet tracked at all, never presented as current, and always labelled wherever they appear:

The backend runs automated ingestion: a sources table tracks every feed’s update cadence and last-checked timestamp, an ingestion-runs log records each import attempt, and indicators are flipped from sample to live one at a time as each source is wired up: see the table below for exactly where each source stands.

Limitations

Indicators are published at different frequencies (weekly, monthly, quarterly). Comparisons across series use each series’ most recent observation at or before a given date, so small timing mismatches are possible. The CPI measures price change, not the absolute cost of living.