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Federal agencies may discount, reject, or in some proceedings exclude expert evidence, but their treatment of that evidence must comply with applicable procedural rules and Administrative Procedure Act review standards. This article explains how agencies evaluate expert input, when arbitrary-and-capricious or substantial-evidence review may apply, and how experts and attorneys can build a clearer administrative record for judicial review.
Yes. A federal agency may decline to credit or adopt expert testimony or technical analysis, and in some proceedings it may exclude evidence under the governing procedural rules. An agency does not have to adopt an expert's opinion simply because the expert is qualified or the submission is scientifically sophisticated.
In many APA challenges, the harder question is whether the agency reasonably considered the relevant record and adequately explained its decision under the applicable standard of judicial review. That standard can vary depending on whether the dispute involves informal rulemaking, formal adjudication, or another type of agency action.
This guide explains how federal agencies may evaluate expert evidence, when that treatment can raise an Administrative Procedure Act (APA) issue, and how experts and legal practitioners can build a clearer administrative record.
Expert input can take different forms depending on the agency proceeding. It is not always "expert testimony" in the courtroom sense.
In notice-and-comment rulemaking under 5 U.S.C. § 553, technical input may include written comments, scientific studies, economic analyses, engineering data, modeling, or other supporting material. In formal hearings governed by § 556, parties may present oral or documentary evidence. Under § 556(e), the hearing transcript, exhibits, and all papers and requests filed in the proceeding constitute the exclusive record for decision in accordance with § 557.
The Federal Rules of Evidence, including Rule 702, generally apply to proceedings in the federal courts identified in Rule 1101. They do not automatically apply to federal agency proceedings as such. Statutes, regulations, or agency-specific procedural rules may instead govern how expert evidence is received and considered, and those requirements are separate from the standards a court later applies when reviewing the agency's action.
The applicable judicial-review standard depends on the type of agency action and the issue being challenged. The APA does not impose one universal "substantial evidence" test.
The main standards include:
Statutory interpretation is a separate question. After Loper Bright Enterprises v. Raimondo, courts independently interpret the governing statute, including the scope of any authority Congress delegated to the agency.
Under Motor Vehicle Manufacturers Association v. State Farm, arbitrary-and-capricious review still requires the agency to make a reasoned decision and explain how the relevant facts support its action.
Yes. A federal agency may decline to credit or adopt expert testimony or technical analysis, and in some proceedings it may exclude evidence under the governing procedural rules. An agency does not have to adopt an expert's opinion simply because the expert is qualified or the submission is scientifically sophisticated.
In many APA challenges, the harder question is whether the agency reasonably considered the relevant record and adequately explained its decision under the applicable standard of judicial review. That standard can vary depending on whether the dispute involves informal rulemaking, formal adjudication, or another type of agency action.
This guide explains how federal agencies may evaluate expert evidence, when that treatment can raise an Administrative Procedure Act (APA) issue, and how experts and legal practitioners can build a clearer administrative record.
Expert input can take different forms depending on the agency proceeding. It is not always "expert testimony" in the courtroom sense.
In notice-and-comment rulemaking under 5 U.S.C. § 553, technical input may include written comments, scientific studies, economic analyses, engineering data, modeling, or other supporting material. In formal hearings governed by § 556, parties may present oral or documentary evidence. Under § 556(e), the hearing transcript, exhibits, and all papers and requests filed in the proceeding constitute the exclusive record for decision in accordance with § 557.
The Federal Rules of Evidence, including Rule 702, generally apply to proceedings in the federal courts identified in Rule 1101. They do not automatically apply to federal agency proceedings as such. Statutes, regulations, or agency-specific procedural rules may instead govern how expert evidence is received and considered, and those requirements are separate from the standards a court later applies when reviewing the agency's action.
The applicable judicial-review standard depends on the type of agency action and the issue being challenged. The APA does not impose one universal "substantial evidence" test.
The main standards include:
Statutory interpretation is a separate question. After Loper Bright Enterprises v. Raimondo, courts independently interpret the governing statute, including the scope of any authority Congress delegated to the agency.
Under Motor Vehicle Manufacturers Association v. State Farm, arbitrary-and-capricious review still requires the agency to make a reasoned decision and explain how the relevant facts support its action.
An agency may disagree with expert evidence or give it less weight when the law permits. Its ultimate action, however, must comply with required procedures and satisfy the relevant standard of judicial review. Whether the agency may exclude evidence depends on the statute, regulations, and procedural rules for the proceeding.
For example, an agency may:
In FCC v. Prometheus Radio Project, the Supreme Court upheld the FCC's decision under arbitrary-and-capricious review despite imperfect empirical data. The Court noted that the FCC acknowledged gaps in its data, considered the studies cited by challengers, and reasonably explained its decision.
An agency's explanation does not have to be perfect, but a reviewing court must be able to follow the agency's own reasoning without supplying a justification the agency never gave.
Under deferential APA or statutory review, courts generally focus on the agency's reasoning and the administrative record. They do not ordinarily choose between competing scientific or technical conclusions themselves.
Baltimore Gas & Electric Co. v. Natural Resources Defense Council illustrates the deference courts may give when an agency makes scientific predictions within its area of special expertise.
Marsh v. Oregon Natural Resources Council similarly recognizes deference when reviewing fact-intensive technical judgments while requiring courts to ensure that the agency made a reasoned decision based on its evaluation of the record.
But an agency's technical expertise does not remove its duty to explain important parts of its decision. In Ohio v. EPA, the Supreme Court concluded at the stay stage that challengers were likely to succeed on an arbitrary-and-capricious claim under the Clean Air Act because the Environmental Protection Agency had not adequately addressed an important concern raised during rulemaking.
In the D.C. Circuit, an agency conducting notice-and-comment rulemaking must give reasoned responses to significant comments that cross the threshold of materiality, although it need not respond separately to every submission.
Experts can strengthen technical submissions by clearly showing their work and connecting the analysis to the issue the agency must decide.
Depending on the discipline and proceeding, an expert may:
Legal practitioners should also make sure, where applicable, that the administrative record preserves important objections, supporting data, and expert responses. Because judicial review generally focuses on the record before the agency, clear documentation can be especially important when technical evidence is disputed.
Can a federal agency ignore expert testimony?
An agency may decline to credit or adopt expert evidence, but it must do so consistently with the standards governing the proceeding. Where arbitrary-and-capricious review applies, failure to address an important aspect of the problem can undermine the agency's reasoning.
Does Federal Rule of Evidence 702 apply to agency expert testimony?
Not automatically. The Federal Rules of Evidence, including Rule 702, generally apply to proceedings in the federal courts identified in Rule 1101. Federal agencies may instead operate under statutes, regulations, or agency-specific evidentiary procedures.
What does "substantial evidence" mean in an administrative case?
Where the substantial-evidence standard applies, the agency's factual findings must be supported by relevant evidence that a reasonable mind could accept as adequate when the record is considered as a whole. In Biestek v. Berryhill, the Supreme Court explained that this threshold is "not high" and requires more than a mere scintilla of evidence. Under APA § 706(2)(E), the standard applies to proceedings subject to §§ 556 and 557 or otherwise reviewed on the record of an agency hearing provided by statute.
Can a reviewing court choose one expert's opinion over another?
Under deferential APA or statutory review, courts generally ask whether the agency's treatment of competing technical evidence satisfies the applicable standard rather than independently reweighing that evidence.
An agency may disagree with expert evidence or give it less weight when the law permits. Its ultimate action, however, must comply with required procedures and satisfy the relevant standard of judicial review. Whether the agency may exclude evidence depends on the statute, regulations, and procedural rules for the proceeding.
For example, an agency may:
In FCC v. Prometheus Radio Project, the Supreme Court upheld the FCC's decision under arbitrary-and-capricious review despite imperfect empirical data. The Court noted that the FCC acknowledged gaps in its data, considered the studies cited by challengers, and reasonably explained its decision.
An agency's explanation does not have to be perfect, but a reviewing court must be able to follow the agency's own reasoning without supplying a justification the agency never gave.
Under deferential APA or statutory review, courts generally focus on the agency's reasoning and the administrative record. They do not ordinarily choose between competing scientific or technical conclusions themselves.
Baltimore Gas & Electric Co. v. Natural Resources Defense Council illustrates the deference courts may give when an agency makes scientific predictions within its area of special expertise.
Marsh v. Oregon Natural Resources Council similarly recognizes deference when reviewing fact-intensive technical judgments while requiring courts to ensure that the agency made a reasoned decision based on its evaluation of the record.
But an agency's technical expertise does not remove its duty to explain important parts of its decision. In Ohio v. EPA, the Supreme Court concluded at the stay stage that challengers were likely to succeed on an arbitrary-and-capricious claim under the Clean Air Act because the Environmental Protection Agency had not adequately addressed an important concern raised during rulemaking.
In the D.C. Circuit, an agency conducting notice-and-comment rulemaking must give reasoned responses to significant comments that cross the threshold of materiality, although it need not respond separately to every submission.
Experts can strengthen technical submissions by clearly showing their work and connecting the analysis to the issue the agency must decide.
Depending on the discipline and proceeding, an expert may:
Legal practitioners should also make sure, where applicable, that the administrative record preserves important objections, supporting data, and expert responses. Because judicial review generally focuses on the record before the agency, clear documentation can be especially important when technical evidence is disputed.
Can a federal agency ignore expert testimony?
An agency may decline to credit or adopt expert evidence, but it must do so consistently with the standards governing the proceeding. Where arbitrary-and-capricious review applies, failure to address an important aspect of the problem can undermine the agency's reasoning.
Does Federal Rule of Evidence 702 apply to agency expert testimony?
Not automatically. The Federal Rules of Evidence, including Rule 702, generally apply to proceedings in the federal courts identified in Rule 1101. Federal agencies may instead operate under statutes, regulations, or agency-specific evidentiary procedures.
What does "substantial evidence" mean in an administrative case?
Where the substantial-evidence standard applies, the agency's factual findings must be supported by relevant evidence that a reasonable mind could accept as adequate when the record is considered as a whole. In Biestek v. Berryhill, the Supreme Court explained that this threshold is "not high" and requires more than a mere scintilla of evidence. Under APA § 706(2)(E), the standard applies to proceedings subject to §§ 556 and 557 or otherwise reviewed on the record of an agency hearing provided by statute.
Can a reviewing court choose one expert's opinion over another?
Under deferential APA or statutory review, courts generally ask whether the agency's treatment of competing technical evidence satisfies the applicable standard rather than independently reweighing that evidence.
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