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 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 are 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
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.