Also known as: but-for cause · but for causation · but-for causation · but-for test · cause in fact
Written by attorneys · grounded in primary & secondary sources — see below
A causal link between conduct and a result that exists when the result would not have occurred without the conduct.
Brian Bailey and Bernard Bass both fire shotguns toward Benito Benitez during a confrontation. One pellet strikes Benitez and causes permanent injury, but forensic evidence cannot identify which gun fired it. Because both men acted negligently and the harm is indivisible, the burden shifts to each to prove his shot was not the but-for cause of the injury.
Bobby Brady stabs Bradley Banks during an argument. Banks survives for nineteen months before dying from complications of the wound. Even though the stabbing clearly satisfied but-for causation for the eventual death, the common-law year-and-a-day rule bars a homicide prosecution.
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Byron Bishop assaults a victim after learning the victim's religion. The government must prove the victim's religion was a but-for reason for the assault under the statute's because-of phrasing.
Bright Path Foods denies Bernard Bass partnership. Evidence shows both legitimate performance concerns and gender stereotyping influenced the decision. Bass must show the stereotyping was a but-for cause of the denial to establish liability.
Police enter Brian Bailey's home without knocking. Bailey moves to suppress evidence found inside. The violation alone does not establish that the evidence would not have been discovered but for the improper entry.
Bristol Steel supplies a pneumatic tool lacking a safety guard. Benito Benitez loses a finger when the tool activates unexpectedly. Expert testimony must show the missing guard was a but-for cause of the injury rather than the worker's own handling.
The plaintiff must show that the injury would not have occurred without the defendant's negligent conduct. This is the factual causation element separate from proximate cause.
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Yes. At common law the rule prevents homicide liability if death occurs more than a year and a day after the wound, regardless of clear but-for causation.
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When multiple negligent defendants could have caused a single indivisible harm and the plaintiff cannot identify which one actually did so, each defendant must prove its conduct was not the but-for cause.
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But-for causation is the primary test for cause in fact. The substantial-factor test applies when multiple causes are each independently sufficient to produce the harm.
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The plaintiff must show the protected trait was a but-for cause of the adverse action, though some statutes allow a motivating-factor showing that then shifts the burden to the employer.
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…what he or she did as well.” In taking issue with this instruction, the defendants argue that the phrase “because of” requires but-for causation—a showing that they would not have acted but for the victim’s actual or perceived religious beliefs. The defendants have the better of the argument. In everyday usage, the phrase “because…