Australian petroleum statistics data is based on a voluntary survey. It may suffer from coverage and classification issues, and is subject to revisions which can result in changes to the size of the estimated tax gap.
There may be timing differences. A timing difference could arise between when product sales data is reported for compilation in the Australian petroleum statistics and when excise data enters ATO systems.
Measurement of volumes may occur at different temperatures. Excise volumes are always adjusted to be measured at 15 degrees Celsius, whereas Australian petroleum statistics volumes may be measured at different temperatures, as survey respondents are not given instructions to adjust to 15 degrees Celsius.
The petrol and diesel excise and duty gap estimate is assessed to be of medium reliability. Although there are some reservations about the data, the methodology employed is robust.
No future developments are expected.