HMRC publishes a breakdown of the tax gap by taxpayer group, tax type and behaviour.16 HMRC told us that it uses the outcomes of its tax gap analysis as indicators 7 Q 23; C&AG’s Report, para 1.12 8 Qq 23–25 9 C&AG’s Report, para 1.14 10 Q 23; C&AG’s Report, para 1.13 11 Qq 23, 25; C&AG’s Report, para 1.19 12 Q 26; C&AG’s Report, Figure 11 13 Q 28 14 Q 19; C&AG’s Report, paras 2.24–2.25 15 Qq 29–30; C&AG’s Report, Figure 14 16 Q 24; C&AG’s Report, para 1.5 Tackling the tax gap 11 of trends in its performance, which allow it to consider its track record in tackling non- compliance in relation to specific behaviour types and taxpayer groups. HMRC, however, confirmed to us that it does not measure the tax gap in each of the four nations of the UK. HMRC told us that it could attribute a proportion of the total tax gap to each of the four nations based on factors such as, the size of the economy and the number of small businesses in different parts of the UK, and assuming that taxpayer behaviours are broadly consistent across the different regions. But it had not undertaken such an analysis.17 HMRC acknowledged that such an analysis could be beneficial, particularly in the context of the devolution of Income Tax powers to Scotland and Wales in 2016–17 and 2019–20 respectively. HMRC told us that the Scottish and Welsh Governments have an interest in how much combined yield it collects and its attribution to them. It said it has a formula to make sure that the yield compliance directorates recover for income tax is shared between Scotland, Wales and the rest of the UK.18