Also known as: mistake doctrine · doctrines of mistake · mistake
Written by attorneys · grounded in primary & secondary sources — see below
An erroneous belief that is not in accord with the facts. The doctrine permits avoidance of contractual obligations or other legal consequences when the mistake is material to a basic assumption, enforcement would be unconscionable, and the risk is not allocated to the mistaken party.
Diana Delgado sold property to Denise Donovan under a contract promising repairs to the roof. At closing the deed omitted any repair obligation. After closing Donovan discovered the roof remained defective. Because both parties shared a mistaken belief about the roof condition at formation, the doctrine of mistake allowed Donovan to pursue relief despite the merger of contract into deed.
Darrell Duncan sued a company he believed was Dakota Industries for a workplace injury. He later learned the proper defendant was Dawson Steel. Because the correct party knew or should have known the suit was intended for it but for the naming mistake, the doctrine of mistake permitted the amended complaint to relate back.
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Davenport Pharmaceuticals was accused of shipping mislabeled drugs. The prosecution offered evidence that the company had committed the same labeling error two years earlier. Because the prior act tended to prove absence of mistake rather than character, the doctrine of mistake supported admission of the evidence for that limited purpose.
Diego Duarte agreed to sell equipment to Devon Drake for a price based on Duarte's mistaken belief that the equipment contained a rare component. Enforcement would have given Drake an enormous windfall. Because the effect of the mistake made enforcement unconscionable, the doctrine of mistake allowed Duarte to avoid the contract.
Dylan Duffy's will omitted a bequest to his daughter because the scrivener mistakenly believed the daughter had predeceased him. In the probate contest the daughter established the mistake. The doctrine of mistake permitted the court to consider the claim that the will did not reflect Duffy's true intent.
Denise Donovan took property she genuinely believed belonged to her under a shared family arrangement. Because her mistaken belief negated the knowledge element required for theft, the doctrine of mistake supplied a complete defense to the criminal charge.
A contract is voidable when one party is mistaken about a basic assumption, the mistake has a material effect on the exchange, and enforcement would be unconscionable or the other party knew of the mistake. The adversely affected party must not bear the risk of the mistake.
Merger normally discharges contract promises not contained in the deed, but the doctrine of mistake creates an exception. Mutual mistake about a basic fact permits relief even after closing.
When a plaintiff sues the wrong party because of a mistake about identity, the doctrine permits the amendment to relate back if the proper party knew or should have known the action was intended for it.
Yes. The doctrine of mistake allows prior similar acts to be offered for the non-propensity purpose of proving that the defendant acted with knowledge or without mistake on the charged occasion.
Ignorance or mistake of fact or law is a defense when it negates the mental state required for a material element of the offense.
…was not; he prepared the list of names by which the clerk filled up commissions and believed Ramsay's name was omitted by mistake. He believed none of the commissions for justices of the peace signed by Mr. Adams were recorded; after being prepared they were carried to Mr. Adams for signature and then back to the…