Federal agencies issue numerous rules pursuant to congressionally delegated authority. These rules have the force and effect of law. The Administrative Procedure Act (APA) generally requires agencies to follow certain procedures when promulgating rules. The statute's "good cause" exception, however, permits age ncies to forgo Section 553's notice and comment requirement if "the agency for good cause finds" that compliance would be "impracticable, unnecessary, or contrary to the public interest" and to bypass its requirement that rules be published 30 days before implementation if good cause exists. In 2012, the Government Accountability Office (GAO) found that between 2003 and 2010 federal agencies issued about 35% of major rules and about 44% of nonmajor rules without a notice of proposed rulemaking (NPRM). Of those rules issued without an NPRM, agencies justified their action most often by invoking the good cause exception. However, federal courts reviewing this agency practice have varied in their analysis—as to the proper standard of review, whether there are actually two good cause provisions, and what factors justify the exception—resulting in confusion as to precisely what constitutes "good cause." This report will examine judicial analysis of the good cause standard and map several factors that lead courts to uphold or reject agencies' invocation of the exception. The APA imposes procedural requirements on the actions of executive branch agencies. Agencies engaged in "formulating, amending, or repealing" a rule are subject to either the APA's formal or informal rulemaking provisions. A rule is "an agency statement of general or particular applicability and future effect designed to implement, interpret, or prescribe law or policy or describing the organization, procedure, or practice requirements of an agency." If an agency's organic statute requires rulemaking to be "on the record," then the APA's formal rulemaking procedures are required. Otherwise, the informal notice and comment rulemaking provisions of Section 553 of the APA apply. The most common process for issuing rules is under the latter category. Section 553 requires agencies to provide the public with notice of a proposed rulemaking. The notice must include "(1) the time, place, and nature of public rulemaking proceedings; (2) reference to the legal authority under which the rule is proposed; and (3) either the terms or substance of the proposed rule or a description of the subjects and issues involved." The public then has an opportunity to submit written comments on the rule. Following consideration of these comments, the agency publishes a final rule with a "concise general statement of [its] basis and purpose." Such rules must be published in the Federal Register not less than 30 days before the effective date. However, the APA contains several exceptions to Section 553's procedural requirements. First, certain subject areas are wholly exempt from the requirements of Section 553. Second, certain "rules" issued by agencies that do not regulate public conduct with the "force and effect of law" are exempt from Section 553's notice and comment requirements. These include rules concerning "agency organization, procedure, or practice," or procedural rules, as well as interpretive rules and general statements of policy, or nonlegislative rules. Such "rules" differ from the substantive, or legislative, rules subject to Section 553 that do bind the public's behavior. Third, certain legislative rules are exempt from Section 553's notice and comment requirement when an "agency for good cause finds" that issuing a proposed rule and holding a comment period would be "impracticable, unnecessary, or contrary to the public interest." Finally, the 30-day publication requirement does not apply when an agency finds good cause. The APA's "good cause" exception(s) thus permits agencies to issue substantive rules that bind the public without following Section 553's notice and comment requirement and to waive the 30-day publication requirement. However, the proper standard for invoking the exemption is unclear; commentators have noted the vagueness of the applicable terms. Federal courts are divided on the proper standard of review when faced with challenges to agencies' use of the exemption to forgo notice and comment procedures. And judicial analysis of agencies' use of the exception appears to consider a wide range of factors without a clear limiting principle. Further, courts divide as to whether a failure to include a formal statement of reasons in the rule when bypassing Section 553's requirements is fatal to the rule's validity. Section 553(b)(B) of the APA provides that compliance with notice and comment rulemaking may be bypassed when an "agency for good cause finds" that doing so would be "impracticable, unnecessary, or contrary to the public interest"; Section 553(d) provides that the 30-day publication rule may be waived for good cause. Some courts have indicated that these are two distinct standards; others do not always distinguish between the two. Courts that do conceptualize them differently note that notice and comment rulemaking allows public participation, while "the purpose of the thirty-day waiting period is to give affected parties a reasonable time to adjust their behavior before the final rule takes effect." In making the latter determination, the D.C. Circuit has noted that agencies "should 'balance the necessity for immediate implementation against principles of fundamental fairness which require that all affected persons be afforded a reasonable amount of time to prepare for the effective date of its ruling.'" In addition, some courts have indicated that the test for good cause to waive notice and comment is more stringent than to waive the 30-day rule. However, courts sometimes decline to decide whether the two standards are different, ruling that the circumstances do or do not support good cause under both exceptions, or do not acknowledge that the two might differ in substance. In fact, some courts distinguished between the two in some cases, but not in others. Whether courts distinguish conceptually between the two standards or not, at a functional level, the two can sometimes operate independently. Courts will sometimes find that good cause exists to issue immediately applicable emergency regulations, but conclude that there is no reason the agency cannot make them temporary, subject to notice and comment procedures. In addition, courts have sometimes found good cause for an agency to issue an immediately applicable interim rule when the agency permits comment on the final rule. Leaving aside disagreements over the proper standard of review, under what circumstances have courts upheld agency invocations of good cause to bypass notice and comment rulemaking? The APA's text limits good cause to an agency finding that compliance with notice and comment rulemaking is "impracticable, unnecessary, or contrary to the public interest." However, judicial application of these factors tends to converge. Consequently, leaving aside minor or technical rules where compliance with Section 553 is unnecessary, it may be helpful to divide good cause cases into several categories: (1) emergencies; (2) contexts where prior notice would subvert the underlying statutory scheme; and (3) situations where Congress intends to w aive Section 553's requirements. Concern for public safety can constitute good cause to bypass notice and comment procedures. For example, in 2004, the D.C. Circuit upheld the Federal Aviation Administration's (FAA) rule, promulgated without notice and comment, covering the suspension and revocation of pilot certificates on security grounds. The agency argued that the regulation was necessary to protect the public against security threats. The court accepted this contention, ruling that the "legitimate concern over the threat of further terrorist acts involving aircraft in the aftermath of September 11, 2001" supported the good cause finding. Likewise, the Ninth Circuit upheld an FAA rule that established special operating procedures for air tour operators. The agency argued that current regulations were insufficient to protect public safety, as the regulation was promulgated after seven helicopter accidents in the preceding year. The court accepted the agency's position and upheld the good cause finding. However, the "mere existence" of a deadline is usually insufficient to establish good cause. Courts have generally rejected good cause exemptions when agencies argue that statutory deadlines alone justify bypassing notice and comment procedures or the 30-day publication requirement. Instead, some "exigency" is required, independent of the deadline itself, which merits dispensing with Section 553's requirements. Importantly, courts have precluded efficiency goals and concern for agency convenience from qualifying as exigencies. For example, courts may find good cause when circumstances outside an agency's control make compliance with notice and comment rulemaking or the 30-day publication requirement impracticable. This can include situations where an agency, faced with a statutory or regulatory deadline to promulgate regulations, invokes good cause to support an order deferring a rule's implementation. This exception is only appropriate in "exceptional circumstances. Otherwise, an agency unwilling to provide notice or an opportunity to comment could simply wait until the eve of a statutory, judicial, or administrative deadline, then raise up the 'good cause' banner and promulgate rules without following APA procedures." For example, the D.C. Circuit ruled that the Office of Personnel Management's deferment of a health plan enrollment period because of recent litigation uncertainty and threats to the financial stability of the program did not violate the APA. In that case, litigation in other courts, combined with losses associated with a major health benefit provider, created an emergency situation wherein commencement of the enrollment period without deferment would have "posed a serious threat to the financial stability of the benefit program." These circumstances were outside of the agency's control, not leaving enough time to comply with notice and comment procedures. Consequently, the court found that good cause existed to waive Section 553's requirements. Similarly, swift action may be permitted when, due to circumstances outside of an agency's control, a regulation is needed in the public interest. For example, in 1981 the Eighth Circuit upheld a temporary FAA rule allocating air carrier slots at National Airport in Washington, DC. Previously, air carriers had traditionally agreed on the appropriate slots through air scheduling committees, which reported their agreement to the FAA. In 1980, for the first time in the scheduling committees' history, the air carriers could not come to an agreement.