We seek feedback and advice about how we estimate the gap from our external and internal subject matter experts. Based on the advice, the reliability for this estimate is high with a score of 21.
The methodological validity of the approach is also assessed as high. The level of data and information held on the high wealth population is extensive and the population coverage informing the estimates is also high.
The gap estimates remain sensitive to assumptions made, particularly relating to non-detection.
Figure 3: Reliability rating scale from very low to very high – high wealth income tax gap