Tax Policy Reform: The Role of Empirical Evidence

To understand the role of evidence in tax policy design, this paper organizes the empirical analysis of reform under five loosely related headings: (i) key margins of adjustment, (ii) measurement of effective tax rates, (iii) the importance of information and complexity, (iv) evidence on the size of responses, and (v) implications from theory for tax design. The context for the discussion is the recently published Mirrlees Review of tax reform. Although the Review focused on all aspects of tax reform, this paper highlights the taxation of earnings. It also comments on earnings taxation in the context of VAT base-broadening reforms and the taxation of capital.