Discussion of “Aggregate Margin Debt and the Divergence of Price from Accounting Fundamentals”

Burger and Curtis (2017) is an empirical investigation of whether aggregate margin debt correlates with aggregate stock prices and aggregate accounting‐based fundamentals. While the paper convincingly documents a significant relation: aggregate margin debt is higher when aggregate fundamentals‐to‐price ratios are low, it fails to document why. The documented relation could exist because margin traders are the overly exuberant noise traders that push stock prices higher away from fundamental values; or the documented relation could be spurious, and exist because aggregate margin debt rises with aggregate price levels simply because margin loan capacity increases as aggregate price levels increase. With insufficiently granular data (aggregate margin debt measured monthly), the authors are not able to sort out why the relation exists. Thus, interpretation of the findings documented in this paper is difficult.     

Measuring the Impacts of Global Trade Reform with Optimal Aggregators of Distortions

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, and—with elasticity estimates suggested by the available econometric evidence—point 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.     

Impacts of China's Accession to the World Trade Organization

This article presents estimates of the impact of China's accessionto the World Trade Organization. China is estimated to be thebiggest beneficiary (US$31 billion a year from trade reformsin preparation for accession and additional gains of $10 billiona year from reforms after accession), followed by its majortrading partners that also undertake liberalization, includingthe economies in North America, Western Europe, and Taiwan (China).Accession will boost manufacturing sectors in China, especiallytextiles and apparel, which will benefit directly from the removalof export quotas. Developing economies competing with Chinain third markets may suffer small losses. Accession will haveimportant distributional consequences for China, with the wagesof skilled and unskilled nonfarm workers rising in real termsand relative to those of farm workers. Possible policy changes,including reductions in barriers to labor mobility and improvementsin rural education, could more than offset these negative impactsand facilitate the development of China's economy.     

The Maple computer algebra system: A review

We set out the main features of Maple V, Release 3, and discuss its potential value to econometricians. Computer algebra systems, of which Maple is a leading example, have developed with the increased power of modern computers, but require skill and patience to use. It seems likely they will find a place in the econometrician's toolkit for work at the interface between analytic and numerical work, where they should prove valuable. However, although Maple has many of the features of conventional statistical/econometric/numerical software, it should not be seen as a substitute.     

Size of employment unit and injury rates in British manufacturing: a secondary analysis of WIRS 1990 data

This article uses unique information provided by the WIRS 1990 dataset in order to explore the relation between size and industrial injury in British manufacturing industry. Results are reported for both independent establishments and for those which form part of larger organisations. The examination of the relation between the injury rate and other variables is permitted by use of a regression model.