Employment size variables were determined from ABS Business Register data. The ABS Business Register is populated using administrative data from the Australian Business Register (ABR) and business data from the Australian Tax Office (ATO). Data on the structures of large and complex businesses are also collected by ABS. The ABS Business Register is updated regularly and a frame of business, containing business characteristic information, is produced quarterly for use in the production of statistics.
The March 2020 quarterly frame was used to determine employment size for businesses reporting their payroll via STP and subsequently allocate their reported payroll jobs against. Once a payroll job is allocated to an employment size category, it is held constant against that category over time. By using the March 2020 quarter frame and holding employment size categorisation constant, the ABS is able to present information about the change in payroll jobs based on the employment size of businesses before Australia recorded its 100th confirmed COVID-19 case on 14 March 2020.
Businesses which are newly created after March 2020 are unable to be assigned a size and are subsequently excluded from the index calculation of employment size groups. These 'new' businesses are included in the calculation of all sizes category (for state and territory, and national level estimates). The number of STP reporting businesses 'born' since Australia recorded its 100th confirmed COVID-19 in March 2020 is considered small, hence their exclusion is expected to have minimal impact on the estimates. The ABS exploring how to incorporate newly created businesses into the employment size estimates and may include them in a future release.