Also known as: arbitrary and capricious · arbitrary or capricious · abuse of discretion · arbitrary and capricious standard · abuse of discretion standard
Written by attorneys · grounded in primary & secondary sources — see below
A standard of judicial review under which a court will set aside an agency's or trial court's action only when the decision lacks a rational basis in the record or rests on clearly erroneous reasoning.
Aisha Ahmed sued a manufacturer after a workplace injury. Her expert linked the injury to a chemical exposure using only anecdotal reports and a large analytical leap. The district court excluded the testimony after finding insufficient data support. On appeal the circuit court affirmed because the exclusion fell within the trial judge's discretion to reject opinions untethered to reliable methodology.
Massachusetts challenged the EPA's refusal to regulate vehicle greenhouse gases. The agency had concluded it lacked statutory authority and that regulation would conflict with other priorities. The Supreme Court held the refusal arbitrary because the statute plainly authorized regulation and the agency had not offered a reasoned explanation for declining to act.
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Plaintiffs sought to enjoin enforcement of an executive order restricting entry from several countries. The district court issued a nationwide preliminary injunction. The Supreme Court reversed the injunction as an abuse of discretion because the plaintiffs had not shown a likelihood of success on their constitutional claims under rational-basis review.
Joshua's mother sued county social services after the agency failed to remove the child from an abusive home. The complaint alleged the agency's inaction violated due process. The Supreme Court held that the agency's decision not to intervene was not subject to the arbitrary-and-capricious standard because no constitutional duty to protect existed.
The NLRB adopted a rule classifying certain buyers as supervisors after notice-and-comment proceedings. An employer challenged the rule as arbitrary. The Supreme Court upheld the rule because the agency had supplied a reasoned explanation based on the record and had not departed from prior policy without justification.
An employer contested an NLRB order finding an unfair labor practice. The record contained conflicting testimony about the employee's conduct. The Supreme Court held that the board's finding must be set aside when substantial evidence on the whole record does not support it.
The agency must examine the relevant data and articulate a satisfactory explanation for its action, including a rational connection between the facts found and the choice made. A court will not substitute its judgment for that of the agency but will set aside action that lacks a rational basis.
Appellate courts review a district court's decision to admit or exclude expert testimony for abuse of discretion. The trial court acts as gatekeeper and may exclude testimony when there is too great an analytical gap between the data and the opinion offered.
Section 706(2)(A) of the Administrative Procedure Act directs courts to set aside agency action found to be arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law.
Under Federal Rule of Civil Procedure 53(f)(5), a court may set aside a master's ruling on a procedural matter only for an abuse of discretion unless the appointing order establishes a different standard.
…Clean Air Act expressly permits review of such an action. § 7607(b)(1). We therefore "may reverse any such action found to be... arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law." § 7607(d)(9). VI On the merits, the first question is whether § 202(a)(1) of the Clean Air Act authorizes EPA to regulate greenhouse gas…