In 2022, we increased the reliability rating largely based on the newly developed model applied for the first time. The new model incorporated significant changes designed to improve the accuracy and reliability of the estimates. Independent external advice endorsed these changes as significant improvements.
In 2023, we have used the same model with updated data and have retained a reliability rating of 'Medium' with a score of 18.
Figure 3: Reliability rating scale from very low to very high – PAYG withholding gap