As a consequence of this process, in normal circumstances the following revisions policy applies for GDP and components.
The September quarter releases normally allow up to 16 quarters of revision (i.e. the quarters of the current year plus the quarters of the previous three financial years) for original current price and chain volume estimates. In these issues, updated annual supply and use benchmarks will be introduced.
In other quarter releases revisions to original current price (and chain volume) estimates are restricted to the current year and the previous financial year.
For chain volume and price measures, the annual re-referencing of the series each September quarter will cause revisions to the levels for the entire series. Re-referencing does not affect percentage movements, but the introduction of updated price weights for the most recent periods could affect growth rates for these periods.
Revisions resulting from seasonal re-analysis are allowed to flow through to the whole seasonally adjusted time series at the time the seasonal reanalysis is undertaken. Traditionally, this occurred in the September quarter release of the national accounts, but with the introduction of concurrent seasonal adjustment, revisions to seasonal factors occur each quarter. GDP and all components were subject to concurrent seasonal adjustment from the September 2006 quarter issue of the national accounts.
From time to time the ABS will also implement an 'historical revision' outside of the normal cycle where the whole historical time series is opened up for revision. Because there has been a number of significant statistical developments in recent years (such as those flowing from the introduction of the new tax system in Australia) there have been three historical revisions since the introduction of supply and use benchmarking in 1997-98.