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 medium with a score of 20.
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. In addition, this year’s gap estimates maintain the current approach to debt, underestimating the final gap estimate. As a result, we have examined more closely the reliability rating to reflect this. For this gap we have downgraded the overall reliability rating to medium.
Figure 3: Reliability rating scale - – high wealth income tax gap