How Much Do Public Comments Change Environmental Reviews?

This 2019 peer-reviewed study by researchers at UC Irvine and UC Davis analyzed draft environmental impact statements, public comments, and final environmental impact statements for 27 California water and energy projects reviewed under NEPA. Although public comments often focused on different concerns than the draft documents, the researchers found little to no substantive change in emphasis between the draft and final environmental reviews.

The study supports the idea that waiting until a formal public-comment period may be too late to have the greatest influence. The authors concluded that public comments had “minimal substantive impact” in the projects they studied and noted that, by the draft stage, only one or two project alternatives were often truly in play. It does not prove that public comments never matter or that projects are secretly predetermined; the authors also acknowledge that earlier scoping and stakeholder involvement may influence a project before the formal comment period begins.

Peer-Reviewed Academic Study