Prices (M1)

The data: coverage, periodicity and timeliness

Coverage characteristics

A price index measures the change in price of a fixed basket of goods and services between two time periods. This change in prices over time is often called inflation.

The price indexes published are the:

• Consumers Price Index (CPI)
• Producers Price Index (PPI)
• House Price Index (HPI)
• Gross Domestic Product (GDP) deflator.

Periodicity

Quarterly

Timeliness

We publish the CPI 12 working days after the end of the reference quarter.

We publish the PPI approximately seven weeks after the end of the reference quarter.

We publish the HPI around four months after the end of the reference quarter.

We publish the GDP deflator around three months after the end of the reference quarter.

Access by the public

Statistics release calendar

The statistics release calendar provides a long-term plan of scheduled releases. We update and release the calendar on the first working day of the month.

View the statistics release calendar

Integrity

Dissemination of terms and conditions under which official statistics are produced, including confidentiality of individual responses

We have reproduced the data with the permission of Statistics New Zealand and PropertyIQ.

Provision of information about revisions and advance notice of major changes in methodology

We generally publish revisions when we update and release a table. New or revised data is in bold font.

Quality

Dissemination of documentation on methodology and sources used in preparing statistics

We sourced data from Statistics New Zealand and PropertyIQ.

Stats NZ

House price index

We produce the factor model and sectoral factor model.

Giannone, D and T Matheson (2006) "A New Core Inflation Measure for New Zealand", Reserve Bank of New Zealand Discussion Paper 2006/10.

Kirker, M (2010) "What drives core inflation? A dynamic factor model analysis of tradable and non-tradable prices", Reserve Bank of New Zealand Discussion paper 2010/13.

Inflation

Consumers price index (CPI)

The CPI measures the changing price of a fixed basket of goods and services purchased by New Zealand households.

There are about 650 goods and services included in the basket. They are classified into 11 groups:

• food
• alcoholic beverages and tobacco
• clothing and footwear
• housing and household utilities
• household contents and services
• health
• transport
• communication
• recreation and culture
• education
• miscellaneous goods and services.

The CPI has an index reference period of the June 2017 quarter (=1000).

Tradable inflation

Tradable inflation covers goods and services that are imported or in competition with foreign goods, either in domestic or foreign markets.

Movements demonstrate how international price movements and exchange rates are affecting consumer prices.

Non-tradable inflation

Non-tradable inflation covers goods and services that do not face foreign competition; for example, government charges. It shows how domestic demand and supply conditions are affecting consumer prices.

Analytical inflation measures

Trimmed mean

The trimmed mean inflation excludes the influence of the largest price increases and decreases in the CPI. This is done at the item level of about 700 goods and services in the CPI basket (for example, 91 octane petrol or strawberries).

The level of trim presented is 10%.

Weighted median

The weighted median inflation is the 50th percentile (by weight) of the distribution of price changes, when the price changes are ranked from highest to lowest.

Factor model

We created the factor model. It is a dynamic factor model that estimates the common component of inflation from all the CPI classes for which data is available. Ninety-six of the 105 classes currently in the CPI are included. The data excludes GST.

For more technical information, see:

A New Core Inflation Measure for New Zealand

Sectoral factor model

We created the sectoral factor model. It estimates the common component of inflation in the CPI basket, the tradable basket, and the non-tradable basket, based upon separate factors for the tradable and non-tradable sectors. The data excludes GST.

For more technical information, see:

What drives core inflation? A dynamic factor model analysis of tradable and non-tradable prices

Some revisions to the sectoral factor model of core inflation

Other price indexes

GDP deflator

The GDP deflator is an implicit price deflator (IPD) calculated by dividing real expenditure GDP by nominal expenditure GDP. It provides a broad measure of price change for total economic activity in New Zealand.

House price index (HPI)

The HPI measures the movement in house prices for local council areas throughout New Zealand, providing an indicator of capital growth and how prices are trending in an area.

Producers price index (PPI)

The inputs index measures the change in costs of production (excluding labour).

The outputs index measures the change in prices received by producers.

The PPI has an index reference period of the December 2010 quarter (=1000).

Symbols and conventions for summary table

General notes

• Individual figures may not sum to the totals due to rounding
• Percentage changes are calculated on unrounded numbers
• You are free to copy, distribute and adapt these statistics subject to the conditions listed on our copyright page.