Measuring the impacts of global trade reform with optimal aggregators of distortions uri icon

abstract

  • Aggregation of trade distortion measures is essential in applied work, but traditional trade-weighted average measures are egregiously flawed. This paper shows how appropriate tariff aggregation can overcome underestimation of both efficiency and terms-of-trade gains from reform. The improvement is shown to result from better measurement of a distortion effect that is most important in the early stages of reform and a weighting effect that becomes more important as protection is reduced. Applications confirm that the technique can be applied relatively easily, andwith elasticity estimates suggested by the available econometric evidencepoint to close to a doubling of the global welfare gains from global trade reform, and dramatic changes in the measured welfare impacts in many individual cases. Sensitivity analysis suggests that, for global trade reform, the ease of substitution between tariff lines is much more important than that between varieties from different countries. We provide an online aggregation tool to allow replication of our analysis or investigation of alternative scenarios for global reform. We hope that this paper will contribute both to wider use of optimal aggregators and improved estimates of the key elasticity parameters.
  • Traditional weighted-average measures of trade distortions are widely used in analyzing global and regional reforms, despite well-known deficiencies. This paper develops and applies optimal aggregators for the real-world case of multiple countries and commodities with much more detailed information on trade than on production and consumption. The approach reflects that different aggregators are needed for expenditure on imported goods and tariff revenues, and allows for incorporation of both intensive and extensive margins of adjustment to reform. Applications confirm that the technique is straightforward enough for widespread use, and point to close to a doubling of the welfare gains at the intensive margin when using the highest possible level of international commodity disaggregation, with larger gains in developing regions than in the industrial countries. The measured income gains increase along the entire path of liberalization, with slightly larger increases in the earlier stages, where the gaps between the responses of the expenditure and tariff revenue aggregators are largest. Sensitivity analysis suggests that, for global trade reform, the ease of substitution between tariff lines is much more important than that between varieties from different countries

publication date

  • 2016
  • 2011
  • 2017
  • 2011