Also known as: but for standard · but-for test · but for test · but-for causation · causation in fact
Written by attorneys · grounded in primary & secondary sources — see below
A test for factual causation that treats conduct as a cause of harm when the harm would not have occurred in its actual manner and timing absent that conduct. Multiple antecedent conditions can each qualify as but-for causes when each is necessary to the outcome. The test supplies the threshold factual inquiry before any further limits on liability are considered.
Brendan Burns stabbed Bernard Bass during a fight. Bernard lingered in a coma for nineteen months before dying from complications of the wound. Prosecutors could not charge homicide because the death fell outside the common-law temporal limit even though the wound remained the necessary condition for the fatal outcome.
Belinda Baxter, a senior manager at Barclay Financial, was passed over for partner after she became pregnant. Evidence showed both her pregnancy and independent performance concerns influenced the decision. The court applied the but-for standard to determine whether the protected trait was necessary to the adverse action.
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Brandon Black, age fifty-eight, was terminated by Bayside Shipping after a reduction in force. He proved that his age was a but-for cause of the selection decision even though the company also cited economic reasons. The court required him to show that he would have kept his job absent consideration of age.
Brittany Bell used a power tool manufactured by Chicago Pneumatic Tool Co. that lacked an adequate guard. The missing guard allowed her hand to contact the blade. The court examined whether the tool would have caused the injury in the absence of the design defect under the but-for test.
Beatrice Brown, a physician at University of Texas Southwestern Medical Center, filed an internal complaint alleging sex discrimination. She was later denied a promotion. The court required her to prove that the complaint was the but-for cause of the adverse decision rather than a mere motivating factor.
Bay Area Systems fired Bernard Bass after learning he was gay. The employer claimed the termination rested on performance issues. The court applied the but-for standard to decide whether the employee would have kept his job had his sexual orientation never been considered.
No. Multiple antecedent conditions can each satisfy the but-for test when each is necessary to the result occurring when and as it did. The presence of another contributing factor does not eliminate the defendant's conduct as a factual cause.
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An omission satisfies the test when the harm would not have occurred in its actual form had the defendant performed the required act. The inquiry focuses on whether timely action would have prevented the result, not on whether other factors also contributed.
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The but-for inquiry is the first, factual step. Only after but-for causation is established do courts consider whether the result is too remote or accidental to support liability under further doctrinal limits.
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Yes. At common law the temporal limit bars homicide charges once the period expires, regardless of whether the defendant's conduct remained a necessary condition for the death.
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…to mean that gender must be irrelevant to employment decisions. To construe the words "because of" as colloquial shorthand for "but-for causation," as does Price Waterhouse, is to misunderstand them. But-for causation is a hypothetical construct. In determining whether a particular factor was a but-for cause of a given event, we…