A CUSMA Chapter 10 binational panel remanded [for further explanation] two statistical methodologies in the US Department of Commerce’s Administrative Review 1 antidumping duty determination on Canadian softwood lumber, requiring Commerce to reassess its use of the Cohen’s d test and to apply weighted pooled variances in its meaningful-difference analysis according to the panel’s Decision and Order. …The panel affirmed all other aspect of the results challenged in this appeal…The review stems from a December 22, 2020 request by Resolute Forest Products and the Ontario Forest Industries Association. …The panel remanded Commerce’s application of Cohen’s d because the Federal Circuit’s decision in Marmen Inc. v. United States Wind Tower Trade Coalition requires that the test’s key assumptions, normal data distribution, equal variances and adequate sample size, be demonstrated before use. …The panel also remanded Commerce’s pooling of variances, directing the Department to use weighted pooled variances that reflect differing sample sizes. …Commerce must respond by October 20, 2025.