A Real-Time Database for GDP
The Reserve Bank analyses a wide variety of data to aid monetary policy decisions. Since many of the key variables are revised over time, taking account of likely revisions is an important component of assessing inflationary pressures. Like the Reserve Bank, private sector forecasters utilise preliminary data and make assumptions about the relationships between those and subsequent measurements. A better understanding of revisions can improve forecasting performance, help reduce uncertainty about inflationary pressures and improve transparency about monetary policy.
As part of the ongoing research into data revisions, the Reserve Bank has compiled a real-time database containing successive quarterly releases of data for the expenditure and production measures of gross domestic product (GDP) and their components. This database is available to external users on the Reserve Bank’s website and will be regularly updated.
The March 2006 Bulletin article “Analysis of revisions to quarterly GDP – a real-time database” (PDF 232KB) by Cath Sleeman provides an introduction for those wishing to use the database and analyses basic revision characteristics in the measures of Expenditure GDP and its components expressed in constant prices and seasonally adjusted. These characteristics include the typical deviation between preliminary measurements and subsequent measurements, the variability of the deviations and time variations in the revision processes.
The data for any given series in the database are stored as a matrix. Each successive column vector of the matrix represents a new vintage of data, containing the most recent measurements available at that vintage date. The database allows users to view the complete set of estimates for a series that have been associated with a given quarter.
The Reserve Bank provides the real-time database to external users without charge. Although every effort has been made to ensure the accuracy of reported measurements, some errors may remain. If you discover any inaccuracies please email the Statistics Unit at firstname.lastname@example.org
It is the user's responsibility to check the accuracy of any data used. The information contained in the database is already in the public domain by way of Statistics New Zealand (SNZ) publications. The data are made available with permission from SNZ.
Production GDP is SNZ’s headline measure of GDP and is considered to be more reliable than Expenditure GDP. The Reserve Bank uses both measures of GDP to inform monetary policy decisions.