Also known as: preponderant · preponderance of the evidence · preponderance of evidence · balance of probabilities
Written by attorneys · grounded in primary & secondary sources — see below
A standard of proof requiring a party to establish that a fact is more likely than not to be true.
Patricia Patel petitioned the probate court to bar her brother from inheriting under their mother's will after the brother was accused of causing the mother's death. The court held a civil hearing and weighed the evidence of the brother's involvement in the fatal crash. Because the evidence showed it was more likely than not that the brother had intentionally caused the death, the court applied the preponderance standard and denied him any share of the estate.
Paul Peterson faced embezzlement charges for diverting nonprofit funds. The prosecution sought to introduce evidence of similar payments Peterson had arranged two years earlier at another organization. The trial court admitted the evidence after finding sufficient proof from which the jury could reasonably conclude the prior acts occurred, without requiring the government to meet the preponderance threshold at the admissibility stage.
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Paula Pierce and Pierce Patterson each claimed they were the intended beneficiary of a bequest to the player who captained the testator's toughest team. Extrinsic evidence showed the testator had used the phrase to describe both individuals at different times. The probate court resolved the ambiguity by determining that the testator's intention in favor of Paula Pierce was established under the preponderance standard.
Phoebe Park was charged in juvenile court with an act that would constitute larceny if committed by an adult. The court applied the preponderance standard to the evidence of her involvement and entered a delinquency finding. Because the standard fell short of the constitutional requirement for criminal cases, the adjudication could not stand.
Pierre Poulin raised an insanity defense at his murder trial. The jury was instructed that it could acquit if the preponderance of the evidence supported his claim of mental incapacity. The instruction allowed the defense to prevail on the lower civil standard rather than requiring proof beyond a reasonable doubt.
Peak Performance sued a pharmaceutical company alleging that a drug caused birth defects. The plaintiffs offered epidemiological studies showing a relative risk exceeding two. The court evaluated whether the studies met the preponderance threshold for proving causation before admitting the expert testimony.
The standard requires the party to prove that a fact is more likely than not to be true. This is the lowest burden of proof recognized in civil litigation and certain preliminary or affirmative-defense contexts.
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The standard is insufficient when the proceeding is criminal in nature or when a fundamental liberty interest such as parental rights is at stake. In those settings due process requires at least clear and convincing evidence or proof beyond a reasonable doubt.
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A final criminal conviction for the felonious and intentional killing of the decedent conclusively establishes slayer status in a subsequent civil proceeding. The civil court need not reweigh the evidence under the preponderance standard once the conviction is final.
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The trial court need not find that the government proved the prior act by a preponderance before admitting it under Rule 404(b). It is enough that the jury could reasonably find the act occurred, provided the evidence survives Rule 403 balancing.
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…that "[a]ny determination at the conclusion of [an adjudicatory] hearing that a [juvenile] did an act or acts must be based on a preponderance of the evidence."[^maj-2] During a subsequent dispositional hearing, appellant was ordered placed in a training school for an initial period of 18 months, subject to annual extensions of his commitment…