CAFC Lets Canadian Gov't, Exporters Appear as Amici in Suit on 'd' Test

The U.S. Court of Appeals for the Federal Circuit on June 13 allowed the Canadian government and a group of eight Canadian lumber exporters to appear as amici curiae in an appeal of the Commerce Department's use of the Cohen's d test to detect "masked" dumping. Judge Kara Stoll granted the motion (Mid Continent Steel & Wire v. United States, Fed. Cir. # 24-1556).

In the case, the Court of International Trade sustained Commerce's use of a simple average of standard deviations in the Cohen's d test denominator in an antidumping duty investigation on steel nails from Taiwan (see 2402120036). The trade court said it couldn't find any fault with Commerce's logic.

In the amici brief, the Canadian parties said the Cohen's d denominator represents the variance of the groups of data, which are tested for differences using the d test (see 2405300050). If the d coefficient is calculated without a denominator that consistently and accurately standardizes mean differences in the numerator, it doesn't provide useful information about the difference between the groups, the brief said.