Reasonable Doubt

This wiki article contains information applicable to United States law only.

A standard of proof that must be surpassed to convict an accused in a criminal proceeding.

Reasonable doubt is a standard of proof used in criminal trials. When a criminal defendant is prosecuted, the prosecutor must prove the defendant's guilt beyond a reasonable doubt. If the jury — or the judge in a bench trial — has a reasonable doubt as to the defendant's guilt, the jury or judge should pronounce the defendant not guilty. Conversely, if the jurors or judge have no doubt as to the defendant's guilt, or if their only doubts are unreasonable doubts, then the prosecutor has proven the defendant's guilt beyond a reasonable doubt and the defendant should be pronounced guilty.

Reasonable doubt has been described a number of ways. One popular description, from the federal jury instructions, holds that proof beyond a reasonable doubt is "proof of such a convincing character that a reasonable person would not hesitate to rely and act upon it in the most important of his own affairs." A judge or juror has reasonable doubt as to a defendant's guilt if, based on all the evidence in the case, the judge or juror would be uncomfortable with a criminal conviction. A criminal conviction imposes public humiliation on the defendant, as well as various hardships such as incarceration, monetary fines, and, in many cases, forfeiture of property.

Reasonable doubt is the highest standard of proof used in court. In civil litigation the standard of proof is either proof by a preponderance of the evidence or proof by clear and convincing evidence. These are lower burdens of proof. A preponderance of the evidence simply means that one side has more evidence in its favor than the other, even by the smallest degree. Clear and convincing evidence is evidence that establishes a high probability that the fact sought to be proved is true. The main reason that the high proof standard of reasonable doubt is used in criminal trials is that criminal trials can result in the deprivation of a defendant's liberty or in the defendant's death, outcomes far more severe than occur in civil trials where money damages is the common remedy.

Reasonable doubt is required in criminal proceedings under the Due Process Clause of the Fifth Amendment to the U.S. Constitution. In In re Winship, 397 U.S. 358, 90 S. Ct. 1068, 25 L. Ed. 2d 368 (1970), the U.S. Supreme Court ruled that the highest standard of proof is grounded on "a fundamental value determination of our society that it is far worse to convict an innocent man than to let a guilty man go free."

The reasonable doubt standard is not used in every stage of a criminal prosecution. The prosecution and defense need not prove beyond a reasonable doubt that every piece of evidence offered into trial is authentic and relevant. If a prosecutor or defendant objects to a piece of evidence, the objecting party must come forward with evidence showing that the disputed evidence should be excluded from trial. Then the trial judge decides to admit or exclude it based on a preponderance of the evidence presented. A similar procedure employing a preponderance standard is used when a party challenges a variety of evidence, such as coerced confessions, illegally seized evidence, and statements extracted without the furnishing of the so-called Miranda warning.

The reasonable doubt standard is inapplicable to still other phases of a criminal prosecution. Lower standards of proof are permissible in parole revocation proceedings, proceedings to revoke probation, and prison inmate disciplinary proceedings.