"Agencies use guidance documents to set regulatory policy on a consistent basis. While 'legislative rules' carry the force of law and are required to undergo the notice and comment procedures of the Administrative Procedure Act (APA), guidance documents are exempt from these constraints and can be issued more swiftly than legislative rules. […] This report examines one type of guidance document of particular recent prominence--agency policy statements. It explores judicial doctrine regarding the difference between legislative rules and statements of policy; discusses when such statements are judicially reviewable; analyzes when courts will grant deference to agency interpretations contained in guidance documents; and notes the relative costs and benefits of potential judicial and statutory rules regarding their use."
CRS Report for Congress, R44468