We seek feedback and advice about how we estimate the gap from our external and internal subject matter experts. Based on the advice and assessment, the reliability rating for this estimate is medium with a score of 19.
The ABS has been impacted by data reliability issues, especially for survey-based series. This may translate to a propensity for larger than normal revisions in future data releases.
The annual measure of the GST liability is influenced by differences in the timing of sales and purchases across the production chain. This is amplified when there is a sharp reduction in demand. The timing mismatch has been heightened across 2019–20 and 2020–21 and so we have smoothed the GST liability to better align with the theoretical GST base.
Tax gap estimates are exposed to both influences. For this reason, we have downgraded the reliability of our estimates from 19 in the previous 2 years to 18 this year. The overall reliability remains medium.
Figure 3: Reliability rating scale from very low to very high – GST gap