Reasonable doubt

{{Redirect|Beyond a reasonable doubt|other uses|Beyond a reasonable doubt (disambiguation)|and|Reasonable doubt (disambiguation)}}

Beyond (a) reasonable doubt is a legal standard of proof required to validate a criminal conviction in most adversarial legal systems.Grechenig, Nicklisch & Thoeni, Punishment Despite Reasonable Doubt - A Public Goods Experiment with Sanctions under Uncertainty, Journal of Empirical Legal Studies (JELS) 2010, vol. 7 (4), p. 847–867 [http://ssrn.com/abstract=1733792 (ssrn).] It is a higher standard of proof than the standard of balance of probabilities (US English: preponderance of the evidence) commonly used in civil cases, reflecting the principle that in criminal cases the stakes are significantly higher: a person found guilty can be deprived of liberty or, in extreme cases, life itself, in addition to the collateral consequences and social stigma attached to conviction. The prosecution bears the burden of presenting compelling evidence that establishes guilt beyond a reasonable doubt; if the trier of fact is not convinced to that standard, the accused is entitled to an acquittal. Originating in part from the principle sometimes called Blackstone's ratio—“It is better that ten guilty persons escape than that one innocent suffer”—the standard is now widely accepted in criminal justice systems throughout common law jurisdictions.

In practice

Because the defendant is presumed innocent, prosecutors must prove each element of the crime charged beyond a reasonable doubt in order to obtain a conviction.{{cite web |title=Amdt14.S1.5.5.5 Guilt Beyond a Reasonable Doubt |url=https://constitution.congress.gov/browse/essay/amdt14-S1-5-5-5/ALDE_00013763/#ALDF_00028992 |website=Constitution Annotated |publisher=United States Congress |access-date=29 December 2024}}{{cite web |title=Presumption of Innocence Burden of Proof (in cases with an affirmative defense) Proof Beyond A Reasonable Doubt |url=https://www.nycourts.gov/judges/cji/1-General/CJI2d.Burden_with_Aff._Defense.pdf |website=New York State Unified Court System |access-date=29 December 2024}} This means the evidence must leave little actual doubt in the mind of the judge or jury that the defendant committed the alleged offense.{{cite web |title=beyond a reasonable doubt |url=https://www.law.cornell.edu/wex/beyond_a_reasonable_doubt |website=Legal Information Institute |publisher=Cornell University |access-date=29 December 2024}} Unreasonable or purely speculative doubts are excluded, whereas doubts grounded in tangible conflicts within the evidence or its sufficiency warrant an acquittal. In many jurisdictions, the phrase “reasonable doubt” remains purposefully undefined in jury instructions to reduce confusion, although critics argue that the lack of a clear definition may itself cause confusion.

Academic literature has identified several possible interpretations of what “reasonable doubt” entails. One approach focuses on whether a doubt can be articulable, meaning grounded in a coherent reason or an alternative narrative, rather than in vague distrust or pure speculation. Critics note, however, that this risks shifting the burden of proof to the defendant if they must articulate reasons to doubt guilt. Another approach frames the inquiry around whether a “reasonable person” would entertain the doubt. But critics observe that this easily becomes circular: a doubt is “reasonable” if a “reasonable” person would hold it, offering little additional guidance. A third, so-called “probabilistic” approach suggests adopting a numerical threshold (e.g., 90% or 95% certainty). Some scholars contend that such explicit quantification reflects the actual logic behind proof standards and is consistent with longstanding principles about balancing the costs of wrongful convictions and wrongful acquittals.

Most legal systems avoid placing an explicit numerical figure on “reasonable doubt” and rely instead on jurors’ or judges’ subjective judgment; however, empirical studies show that laypeople vary widely in the probability threshold they associate with “beyond a reasonable doubt.”Kagehiro, Dorothy K. and W. Clark Staunton, [https://www.semanticscholar.org/paper/Legal-vs.-quantified-definitions-of-standards-of-Kagehiro-Stanton/d89fec62b534ac38d985307846710fe98c868f5f Legal v. Quantified Definitions of the Standard of Proof], 9 L. Hum. Behav. 159 (1985)Simon & Mahan, Quantifying Burdens of Proof: A View from the Bench, the Jury, and the Classroom, 5 L. & Soc’y Rev. 319 (1971) Some scholars have proposed that a probabilistic or numerical approach—e.g., equating “reasonable doubt” to a particular probability threshold—can mitigate these inconsistencies.Pi, Daniel, Francesco Parisi, and Barbara Luppi, Quantifying Reasonable Doubt, 72 Rutgers U. L. Rev. 455 (2020)

Definitions and critiques

Critics of the standard, including some jurists and legal scholars, point out that the instruction “beyond a reasonable doubt” can be circular: it does not clarify how certain the jury must be, only that it must be “more certain” than other standards (such as preponderance of the evidence).In re Winship, 397 U.S. 358 (1970) Various courts have tried to elaborate with phrases such as “the kind of doubt that would make a person hesitate to act,” or “moral certainty,” but these have often been deemed unhelpful or potentially confusing.

Research suggests that where the law intends a clear distinction between “preponderance,” “clear and convincing evidence,” and “beyond a reasonable doubt,” jurors given only verbal formulations struggle to separate these levels in practice. Studies of mock jurors have found no consistent difference in outcomes under purely verbal instructions. By contrast, instructions incorporating some numerical guidance produce more consistent results.Kagehiro, Dorothy K., Defining the Standard of Proof in Jury Instructions, 1 Psychol. Sci. 194 (1990)

By jurisdiction

=England and Wales=

In Woolmington v DPP (1935), the House of Lords famously declared that there is a “golden thread” running through English criminal law, that it is the duty of the prosecution to prove the defendant's guilt.[http://www.bailii.org/uk/cases/UKHL/1935/1.html Woolmington v DPP] [1935] UKHL 1 (23 May 1935)

In England and Wales, the modern practice often avoids the phrase “beyond reasonable doubt” in favor of telling jurors they must be “sure” of the defendant’s guilt. This rewording follows appeals court rulings expressing concern that the traditional formula might confuse jurors.[http://www.bailii.org/ew/cases/EWCA/Crim/2009/2563.html R v Majid] [2009] EWCA Crim 2563

=Canada=

The Supreme Court of Canada has emphasized that jurors should be told the prosecution bears the entire burden and that the doubt must be based on reason and common sense. In R. v. Lifchus, the Court advised jurors that absolute certainty is not required, only that they be “sure” based on the evidence, and that proof of probable guilt is insufficient.{{Cite court

|litigants = R. v. Lifchus

|vol = [1997] 3

|reporter = SCR

|opinion = 320

|court = SCC

|date = 1997

|url=http://www.canlii.org/en/ca/scc/doc/1997/1997canlii319/1997canlii319.html

}} Later cases, such as R. v. Starr, clarified that “proof beyond a reasonable doubt” lies much closer to absolute certainty than to a balance of probabilities.{{Cite court

|litigants = R. v. Starr

|vol = [2000] 2

|reporter = SCR

|opinion = 144

|pinpoint = 242

|court = SCC

|date = 2000

|url=http://canlii.ca/en/ca/scc/doc/2000/2000scc40/2000scc40.html

}}

=United States=

In the United States, the notion that an accused must be found guilty “beyond a reasonable doubt” is constitutionally mandated under the Due Process Clause.In re Winship, 397 U.S. 358, 364 (1970) Although the Supreme Court has discussed this standard in several decisions, it has resisted providing a strict definition; indeed, it has stated that attempts to define the term often “do not usually result in making it any clearer to the minds of the jury.”Holland v. United States, 348 U.S. 121, 140 (1954) Critics argue that juror misunderstanding of what “reasonable doubt” requires contributes to inconsistent outcomes and complicates the fairness of the justice system.

Many proposals to quantify “beyond a reasonable doubt” draw upon the so-called Blackstonian ratio—for example, equating “It is better that ten guilty persons escape than that one innocent suffer” to a 90% threshold of certainty. However, courts vary substantially in how they refer to or adopt Blackstone’s formulation. Some imply a ratio of 1:5 or 1:10, while others have cited values as high as 1:99, resulting in no single uniform benchmark nationwide. Recent scholarship has attempted to catalogue the implicit level of certainty state-by-state.

=Japan=

Japan uses a high standard of persuasion in criminal cases, influenced by the principle of in dubio pro reo (when in doubt, rule for the accused), but judges sometimes diverge in how strictly they apply it.Goodman, Carl F., Rule of Law in Japan: A Comparative Analysis (Kluwer Law International, 2003), pp. 253–54.