Following Tree Frog News’ November 7 op-ed, “Rigged by Design? How Method and Policy Keep U.S. Lumber Duties High”, the US Lumber Coalition responded (Understanding Why Duties Persist — Not Because of Arbitrary Math, But Because of Past and Ongoing Harm) noting that the Department of Commerce did not use “zeroing” in its latest anti-dumping calculation. The note below clarifies what Commerce actually applied and what remains unresolved.

Following publication, the US Lumber Coalition pointed out that the Department of Commerce did not use “zeroing” in its latest anti-dumping calculation. In reviewing the record, Tree Frog News found that Commerce applied a differential-pricing framework, which uses statistical tests to determine comparison methods.¹ However, a 2020 WTO panel found that this framework could produce mathematically similar distortions to zeroing — in effect, “replicating the problem without using the name.”² but because the most recent review record is largely redacted and the WTO Appellate Body remains inactive, there has been no external review of how this method performed in the most recent review.

The more important question, then, is whether the procedural change has addressed the sources of bias identified in past WTO rulings — specifically in how Commerce calculates anti-dumping margins, measures subsidies, and selects its review periods — which continue to produce duty levels that appear inconsistent with actual market conditions. Tree Frog News will continue to report as new information emerges. 

¹ US Department of Commerce, Issues and Decision Memorandum – Softwood Lumber from Canada, Final Results 2023 (7 Aug 2025), noting use of “differential pricing analysis” to determine comparison methods.
² WTO, US – Countervailing Duty Measures on Softwood Lumber from Canada (WT/DS533/R, 2020), paras. 7.131–7.145, finding that the differential-pricing approach can distort results in ways comparable to zeroing.