This study considers advantages of relying on micro-data to assess average tax rates on labour, capital and transfer income and presents some illustrative results. The analysis emphases the importance of matching taxpayer-level information to income flows, and notes difficulties in interpreting tax rates that average over all taxpayers. It also illustrates the importance of loss adjustments in measuring effective tax rates on capital income, and reports evidence of significant variation in corporate average tax rates by sector and firm asset size.