policy-imposing country by trading partner and by year in a conservative way that does not allow for redundancy.<sup>14</sup> In robustness checks, we also construct this variable using the antidumping policy alone and using all (non-redundant) TTB investigations, even those that did not result in the imposition of new import restrictions.

A second innovation relative to the prior literature is emphasis on a number of bilaterallydefined explanatory variables which enable us to focus on relationships between a policy-imposing economy and its key trading partners.<sup>15</sup> This is empirically relevant for two reasons. First, the temporary trade barriers under study can be imposed bilaterally so as to discriminate across import sources. Second, two of the key macroeconomic determinants of import protection in our model - trading partner _i_ ’s real GDP growth and the bilateral real exchange rate - vary bilaterally. Our dataset with bilateral variation also allows us to examine if countries apply import protection against trading partners facing their own economic shocks.

There are three main differences in variable construction relative to the approach adopted in Bown and Crowley (2013a). The first distinction is this paper’s use of data at the annual frequency, a limitation that the companion paper is able to overcome because data at the quarterly frequency is available for only a smaller set of high income economies. Second, due to data limitations for a number of emerging economies, we generally use domestic real GDP growth to capture the slowdown of the economy, whereas the companion paper used either the change in domestic unemployment rate or real GDP growth. The unemployment rate data series is not sufficiently available for all of the emerging economies in our analysis to use in the baseline estimates; however, we do employ it where 14 At any point in time in the sample period under the Harmonized System, there are roughly 5000 HS-06 imported products that could be imported from any particular trading partner. In terms of policy, governments impose these import restrictions at the 8- or 10-digit product level; unfortunately the HS-06 level is the most finely disaggregated level of data that is comparable across countries. First, so as to avoid double counting in cases in which new import protection at the 8-digit level falls into the same HS-06 category as a previously imposed measure, we do not include such products. Second, for the more expansive import protection measure covering all four policies, we also do not include products that were subject to a simultaneous or previously imposed TTB under a different policy. This phenomenon is particularly relevant as most countervailing duties are imposed simultaneously with antidumping duties on the same products. For a discussion, see Bown (2011).

> 15 The Appendix lists the trading partners _i_ for each of our thirteen policy-imposing economies. We condition on major trading partners affected by TTBs given that our estimation includes country fixed effects that would otherwise explain non-application against countries that a particular imposing country never targeted. Nevertheless, the trading partners included in our dataset are generally found to be the source of more than two thirds of the policy-imposing economies’ non-oil imports during the sample period, ranging from 65 percent for Thailand to 91 percent for Mexico. The Philippines is a notable outlier for which the available bilateral trading partners comprise only 38 percent of non-oil imports.

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