Agencies often are given discretion about whether and when to address a problem. The modem administrative state is characterized by broad delegations of policy matters to agencies under statutes that merely identify the area within which the agency is to exercise power. Statutes frequently fail to direct an agency to focus on particular problems within the ambit of an agency's regulatory authority and rarely demand that agencies actually regulate particular conduct of those whom the statute potentially subjects to agency jurisdiction.' Flexibility, which is meant to allow an agency to react to changing circumstances more quickly than can Congress, is one justification for granting agencies such broad discretion. Responding to a problem can demand the collection and analysis of vast amounts of information to try to determine the cause of the problem and the likely impacts of any solution. Arguably, agencies have expertise, enjoy relationships with the stakeholders involved in any controversy within the agency's authority, and operate in accordance with fairly simple rulemaking procedures, all of which facilitate such collection and analysis of data. In addition, agencies are divorced, at least to some extent, from direct political pressures, and because their actions are national in scope, often have less need to placate special interest constituents than do members of Congress. Over the past two decades, administrative law scholars have identified hard look judicial review of agency action under the arbitrary and capricious