Many federal agencies are running substantial legal risks by providing inadequate notice of significant regulatory changes. That is one of the conclusions we reached after a year-long study for the Administrative Conference of the United States (ACUS). The goal of the study was to review how agencies provide notice of significant regulatory changes so that ACUS could decide whether to recommend improvements. We interviewed a broad range of interested parties: agency staff, regulated parties, regulatory beneficiaries, business groups, public interest NGOs, unions, micro-businesses, and others. Following deliberations informed by our study, ACUS adopted a recommendation earlier this year that provides guidance to agencies about how to provid...