Also known as: causation requirements · causation · causal requirement
Written by attorneys · grounded in primary & secondary sources — see below
A legal prerequisite that a party's conduct must have produced or contributed to a specified harm or consequence before liability or other legal effect attaches. The requirement demands proof that the conduct was a but-for or substantial factor in bringing about the result, subject to doctrinal limits such as burden shifting in multi-defendant cases or temporal cutoffs in homicide.
Corinne Cho and Charles Cunningham both detonated explosives near a shared quarry wall without coordinating safety zones. A rockslide injured Connor Clark, but no witness could identify which blast dislodged the fatal boulder. Because factual causation cannot be traced, each defendant must prove his blast did not cause the injury. Failure to do so leaves both liable for Clark's damages.
Carlos Castillo stabbed Catherine Carter during an argument. Carter lingered in a coma for fourteen months before dying from complications. Prosecutors cannot charge homicide even though the wound was the but-for cause of death, because the common-law temporal limit expired before the victim died.
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Cypress Technologies installed a faulty valve that leaked coolant into a river. Compass Logistics later dumped additional chemicals at the same site. When residents sued both firms for downstream contamination, the trial judge alone determined whether Cypress's valve was a substantial factor in the harm and whether the damages could be apportioned, because reasonable jurors could not differ on those questions.
Colin Chambers assaulted a witness who had agreed to testify against him. The witness later refused to appear out of fear. The prosecution cannot introduce the witness's prior statements under the forfeiture doctrine because Chambers acted only to silence the witness through violence, not with the specific purpose of preventing courtroom testimony.
Continental Bank’s medical-device division sold a hip implant without warning physicians of a known fracture risk. Patient Connor Clark received the implant and later suffered a break. Clark cannot recover against the manufacturer because he offered only general evidence that physicians knew of risks. He failed to show that a proper warning would have changed his own physician’s prescribing choice.
Copperfield Mining challenged an EPA rule limiting plant emissions. The company alleged that its operations would suffer economic harm if the rule took effect. The court dismissed the suit because Copperfield could not demonstrate that its claimed injury was caused by the EPA’s failure to regulate rather than by independent market forces.
The burden shifts when two or more defendants acted negligently toward the plaintiff, the plaintiff suffered a single indivisible harm, and it is impossible to determine which defendant’s act caused the injury. Each defendant must then prove its conduct was not the cause in fact. Otherwise all remain liable.
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Yes. At common law the prosecution cannot charge homicide if the victim dies more than a year and a day after the wound, even when the defendant’s conduct plainly caused the death.
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The plaintiff must demonstrate that an adequate warning to the prescribing physician would have changed the physician’s decision to prescribe the device or drug. Generalized evidence that physicians knew of risks is insufficient.
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No. The doctrine requires proof that the defendant engaged in conduct designed to prevent the witness from testifying. Causing unavailability without that intent does not forfeit confrontation rights.
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…one of degree." To the same effect is the concurring opinion of Justice Cardozo in Schechter Poultry : "There is a view of causation that would obliterate the distinction between what is national and what is local in the activities of commerce. Motion at the outer rim is communicated perceptibly, though minutely, to…