Legal Theory Lexicon 090: Adjudicative Facts versus Legislative Facts

By Lawrence B. Solum

Introduction

Facts are important to the outcome of legal disputes. One of the things that law students may notice is that there are different kinds of factual disputes that arise in legal proceedings. Some factual disputes are about events, occurrences, and transactions that are mostly relevant to the particular dispute–the civil action or the criminal prosecution. Other facts are more general and bear on questions about what the law is or should be–and not what happened in a particular case. The distinction between these two kinds of facts is sometimes marked by using the labels “adjudicative facts” and “legislative facts.” This entry in the Legal Theory Lexicon provides a brief introduction to that idea.

Origins of the Distinction in Administrative Law

The use of the terms “adjudicative facts” and “legislative facts” is strongly associated with a 1942 article by Kenneth Culp Davis, the author of a famous treatise on administrative law. Here is Davis’s discussion of the distinction:

Through adjudication administrative agencies create law and determine policy, as well as make findings which concern only the parties to the specific case. Creation of law and determination of policy usually do not rest upon uninformed a priori judgments having only an ethical or a logical basis. Frequently agencies’ choices of law or policy must depend on fact-finding. But the fact-finding process for such purposes is different from the process of finding facts which concern only the parties to a particular case and calls for different rules of evidence.

When an agency finds facts concerning immediate parties — what the parties did, what the circumstances were, what the background conditions were — the agency is performing an adjudicative function, and the facts may conveniently be called adjudicative facts. When an agency wrestles with a question of law or policy, it is acting legislatively, just as judges have created the common law through judicial legislation, and the facts which inform its legislative judgment may conveniently be denominated legislative facts. The distinction is important; the traditional rules of evidence are designed for adjudicative facts, and unnecessary confusion results from attempting to apply the traditional rules to legislative facts.

Kenneth Culp Davis, An Approach to Problems of Evidence in the Administrative Process, 55 Harv. L. Rev. 364, 402–03 (1942).

Davis makes the important point that adjudicative factfinding is governed by the rules of evidence–a formal system that governs the admissibility of evidence and by associated procedures for the questioning of witnesses and the presentation of documentary and physical evidence. But these rules are not observed in factfinding processes associated with lawmaking. Congressional hearings and factfinding by administrative agencies are not governed by the rules of evidence. Scientific evidence is introduced at trial via expert witnesses, but legislative and administrative factfinding can proceed in much less formal ways.

Constitutional Facts

Davis modeled his notion of legislative facts on the already-existing category of constitutional facts. Such facts may be developed as part of the record at trial, but as Professor Davis notes in his article, such facts are frequently brought before a court by briefs that cite research that is published in scientific journals or monographs. Such facts are outside the record and do not fit within the traditional categories of facts of which judges may take “judicial notice.’

Constitutional facts become important when courts apply tests that involve the scrutiny of means ends relationships and assessment of the importance of goals pursued by legislation or executive action. For example, the strict scrutiny test requires a compelling state interest and demonstration that the means employed by government action are necessary to achieve such ends. The importance of ends and the fit between ends and means frequently depend on empirical questions–hence the need for constitutional factfinding.

Deference to Extrajudicial Findings of Legislative Facts

When courts assess legislative facts, they may need to take into account factfinding that has already been done by a legislature, executive official, or a regulatory agency. This raises questions about “deference.” Should a court defer to factfinding done by the legislative or executive branch? And what sort of deference is appropriate? Rational basis review usually involves considerable deference. At one extreme, the courts may defer to a legislature so long as the legislature could rationally have found facts that supported its decision, even if the legislature did not actually engage in factfinding and even if the great weight of the evidence does not support a legislative fact that is required for legislation to be upheld. But if the standard of review is strict scrutiny, courts may give legislative factfinding no deference at all, striking down legislation if the court’s view of the facts does not support legislative or executive action.

Legislative Facts and the Role of Judges

The importance of legislative facts may be related to conceptions of the proper role of judges. For example, Formalists may believe that constitutional and statutory interpretation should largely be driven by the “meaning” or communicative content of the text. In the realm of common law, the formalist approach emphasizes adherence to precedent. On the formalist conception of the judicial role, judges do not make law, minimizing the need for legislative factfinding by judges. Realist or instrumentalist theories of judging are different: they do not draw a sharp line between law making and law application. If the role of judges is to make policy, then judges may need to engage in substantial legislative factfinding. In particular, the application of “balancing tests” may require judges to engage in legislative factfinding in order to determine the weight of the various interests to be balanced.

Treating Meaning-Establishing Facts as Adjudicative Facts

The distinction between adjudicative and legislative facts has taken on new significance in the context of originalism and textualism. Both approaches maintain that the meaning of a legal text is an empirical matter—determined by facts about linguistic usage and historical practice at the relevant time and place. This raises a pressing question: if original meaning and plain meaning are genuinely factual questions, should they be developed as adjudicative facts, subject to the rules of evidence, expert testimony, and adversarial testing at the trial level?

Some scholars and courts have moved in this direction. After the Supreme Court’s decision in New York State Rifle & Pistol Ass’n v. Bruen, 597 U.S. 1 (2022), which requires courts to assess whether modern firearms regulations have historical analogues in the founding era, many district courts held evidentiary hearings in which historians testified as expert witnesses. Joseph Blocher and Brandon Garrett have argued that this is how originalist fact-finding should work: because our legal system gives trial courts primary authority over factual determinations, historical and linguistic facts bearing on constitutional meaning should be developed through adjudicative procedures, with adversarial testing, deference on appeal, and the other procedural protections that accompany the finding of adjudicative facts.

There are powerful objections to this approach, however. The most significant is the uniformity problem: if the original meaning of a constitutional provision or the plain meaning of a statutory term is an adjudicative fact to be determined by each trial court in each case, different courts could reach different conclusions, and those conclusions would be entitled to deference on appeal. A statute would then mean one thing in the Northern District of California and something different in the Southern District of Texas—or even different things in successive cases before the same court. This outcome is in deep tension with the basic premise of statutory and constitutional interpretation: that a legal text has a single legally authoritative meaning applicable uniformly across all cases and parties. On this view, facts that establish the meaning of legal texts function more like legislative facts, to be determined by appellate courts—and ultimately by the Supreme Court—with full de novo review rather than case-by-case adjudicative fact-finding.

Conclusion

There is much more to be said about the distinction between adjudicative facts and legislative facts, but I hope that this Lexicon entry provides you with a sense of the conceptual content of the distinction and its implications.

Related Lexicon Entries

Bibliography

Joseph Blocher & Brandon L. Garrett, Originalism and Historical Fact-Finding, 112 Geo. L.J. 699 (2024).
Caitlin E. Borgmann, Appellate Review of Social Facts in Constitutional Rights Cases, 101 Calif. L. Rev. 1185 (2013).
Kenneth Culp Davis, An Approach to Problems of Evidence in the Administrative Process, 55 Harv. L. Rev. 364 (1942).
Neal Devins, Congressional Factfinding and the Scope of Judicial Review: A Preliminary Analysis, 50 Duke L.J. 1169 (2001).
Timothy B. Dyk, The Role of Non-Adjudicative Facts in Judicial Decisionmaking, 76 Stan. L. Rev. Online 10 (2023).
David L. Faigman, Constitutional Fictions: A Unified Theory of Constitutional Facts (Oxford Univ. Press 2008).
Brianne J. Gorod, The Adversarial Myth: Appellate Court Extra-Record Factfinding, 61 Duke L.J. 1 (2011).
Allison Orr Larsen, Confronting Supreme Court Fact Finding, 98 Va. L. Rev. 1255 (2012).
Allison Orr Larsen, Constitutional Law in an Age of Alternative Facts, 93 N.Y.U. L. Rev. 175 (2018).
Haley N. Proctor, Rethinking Legislative Facts, 99 Notre Dame L. Rev. 955 (2024).
Ann Woolhandler, Rethinking the Judicial Reception of Legislative Facts, 41 Vand. L. Rev. 111 (1988).

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Legal Theory Lexicon 090: Adjudicative Facts versus Legislative Facts

(Last revised on December 21, 2025.)

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