We seek feedback and advice on how we estimate the gap from our external and internal subject matter experts. Based on that advice and their assessment, the reliability rating for these gap estimates is medium, with a score of 17.
This gap program we have improved the data applied to more reliably estimate the house and land sales component of the GST base and the timing that they enter the GST base. This likely improves the reliability and accuracy of the gap estimates; especially around quantifying the theoretical fully compliant GST base associated with property transactions.
The Australian Bureau of Statistics (ABS) has also started using its Monthly Household Spending Indicator compiled using aggregated, de-identified card transactions data from participating banks, supermarket transactions data and new vehicle sales data. This is a step forward in terms of coverage, timeliness and accuracy of published data around consumer spending in Household final consumption expenditure, and likely improves the reliability and accuracy of the data underpinning GST top-down gap estimates.
Whilst positive, these improvements are not considered to materially impact the overall reliability of GST gap estimates.
Overall, we therefore recommend that the reliability rating remains at 17 (medium); the same as for the 2023 and 2024 programs.
Figure 3: Reliability rating scale – GST gap