In the lead up to the June 2020 Wage Price Index release, the ABS advised that the method used to produce seasonally adjusted estimates would change from the "concurrent" method to the "forward factors" method during the COVID-19 period. The forward factors approach is better suited to managing large movements at the end point of series and ensures that these large movements do not have a disproportionate influence on the seasonal factors.
Given the disruption to the labour market during the COVID-19 period and the continuing use of the forward factors method to seasonal adjustment, the ABS recently undertook an extensive annual review of its seasonally adjusted Wage Price Index series. This review followed similar reviews that are progressively being undertaken across the ABS economic statistics program, and the outcome for Wage Price Index was to continue using the forward factors method. Through this process static forward factors were calculated for the next 4 quarters and implemented in the June 2021 release.
Further information can be found in the ABS article published on 23 July 2020 (Measuring the Wage Price Index during the COVID-19 pandemic).
The seasonally adjusted Wage Price Index series will continue to use the forward factors method for the foreseeable future and are expected to return to using concurrent adjustment when the risk of disruption from COVID-19 becomes sufficiently low.