incentives to file anti-dumping cases, as it directed the collected tariff revenues to the filing firms.<sup>29</sup> We focus on cases filed after January 1, 2001, the day the Act went into effect.<sup>30</sup> The results are contained in Table 6 and are once again are broadly consistent with the compound shock thesis. A relative supply shock is evident in column (4), though its origin appears to be slightly later than documented for steel products. The negative domestic demand shock is also documented with a decline in imports from all sources of 11 percent.

Evidence from the steel and Byrd cases illustrates that the compound shock thesis is consistent across important subsamples. Of course, deviations from the pattern identified above could occur within other subsamples. Nonetheless, these two seem to be natural and obvious subsamples in which to evaluate the robustness of the pattern observed in the complete sample. On the basis of these exercises, the compound shock thesis appears to be a robust aspect of filing behavior.

# **6 Conclusion**

While the global trading system generally supports open trading arrangements, it also allows room for substantial policy exceptions. These exceptions are quite narrow, and can be applied in a discriminating manner. The narrowness of the product space in which policy can be applied, and the discriminating use allows a research design that exploits relative differences in import dynamics - across countries and across similar products - to relate changes in import competition to industry demands for protection. Knowing more about the use of exceptions can help us better understand the pressures that drive trade policy, and perhaps even the benefits of the wider system of restraint.

Our study of filing behavior in U.S. AD policy indicates that domestic industries’ demands for protection, in the form of AD petitions, typically follow a pattern of compound shocks. Approximately 15 months prior to the filing of a petition, an initial positive relative supply shock favors exports from those countries that will subsequently be named in a petition, but not exports from other countries. In terms of product space this shock is a broad one, hitting the products named

> 29Reynolds (2006) finds evidence that the Byrd Amendment increased the number of petitions filed. Reynolds and Liebman (2006) identify a relationship between firms that gain from the amendment, their contributions to members of Congress and members’ support for the Amendment. Reynolds and Liebman (2006) contains a description of the amendment as well as a legislative history.

> 30The sample split captures more than the change in the law of course. There is a change in presidential administrations at this time. There are also changes in macroeconomic phenomena such as a reduced average GDP growth rate and a shift in the direction of the USD exchange rate that roughly coincide with this split. The subsample considered also contains relatively few steel cases, as the steel safeguard action implemented in March of 2002 limits the number of AD cases in steel. Our sample split is thus a rough robustness check against the possibility that any of these phenomena, including the Byrd Amendment, might affect our results.

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