For public interest advocates engaged on issues of worker health and safety and environmental protections, regulatory cost-benefit analysis has long been seen as an obstacle to meaningful progress. In November 2023, the Biden administration overhauled Circular A-4, which provides guidance to agencies on how to perform cost-benefit analyses for their rules. The reforms seek to make cost-benefit analysis less biased against worker safety, public health, environmental, and other protective safeguards. As such, the new version of Circular A-4 offers important new levers to agencies to justify more stringent protections. By extension, those in the public interest community can use agency implementation of the new Circular A-4 as part of their advocacy efforts for specific rules they are tracking. This article seeks to support this tactic by providing a roadmap for advocates on how to incorporate into their comments critiques of agencies' cost-benefit analyses based on the Circular A-4 revisions.