[Excerpt] This report summarizes the evidence on the relationship between tax rates and economic growth, referring in a number of cases to more-detailed CRS reports. Potentially negative effects of tax rates on economic growth have been an issue in the debate about whether to increase taxes to address the budget deficit and whether to broaden the base and lower the rates with tax reform. After first distinguishing between short-run counter-cyclical considerations and long-run growth effects, the following section provides some historical data on tax rates and measures of factor supply and growth. This report then reviews the empirical evidence on the major contributors to growth. The final section concludes with a review of dynamic scoring issues.