The Built‐in Flexibility of Income and Consumption Taxes

This paper reviews, and synthesises within a uniform framework, a number of analytical results on the built‐in flexibility of taxation. Established results for income taxes are reviewed and integrated with recent results for consumption taxes. These help to provide a better understanding of the determinants of the revenue responsiveness properties of different taxes. They also provide convenient expressions for the calculation of tax revenue elasticities in practice. It is shown that the magnitude of revenue elasticities can be expected to differ substantially for alternative taxes, for different forms of the same tax, and for the same tax over time as incomes change relative to tax thresholds and as consumption patterns change. These results are especially relevant for the many industrialised countries which have undertaken major fiscal reforms in recent years with, often unintended, consequences for revenue elasticities.