Also known as: substantial factor · motivating factor · mixed-motive test
Written by attorneys · grounded in primary & secondary sources — see below
2 senses
A contributing cause that plays a significant role in producing harm even when other forces operate simultaneously. The presence of an independent sufficient cause does not automatically relieve the actor of responsibility when the negligent conduct actively contributes to the outcome.
A contributing cause that plays a significant role in producing harm even when other forces operate simultaneously. The presence of an independent sufficient cause does not automatically relieve the actor of responsibility when the negligent conduct actively contributes to the outcome.
Select any source to read its text and confirm it supports the definition.
A protected activity or characteristic that influences an adverse governmental or employment decision. Once shown, the burden shifts to the defendant to prove the same action would have occurred absent the protected conduct.
Select any source to read its text and confirm it supports the definition.
A protected activity or characteristic that influences an adverse governmental or employment decision. Once shown, the burden shifts to the defendant to prove the same action would have occurred absent the protected conduct.
Each sense below has its own examples, sources, and questions.
Darlene drove a truck with worn brakes down a steep grade. A rockslide blocked the road ahead. Either the slide or the brake failure alone would have caused the crash into Silas's car. A jury could find Noon Dispatch's negligence a substantial factor because both forces operated actively and each was independently sufficient.
Maple Teach left a handrail loose and a safety glove torn. Yuri fell on darkened stairs while using the glove. The handrail detachment and glove defect each increased the chance and severity of burns and fractures. A jury could treat the university's omissions as a substantial factor given the number and extent of contributing defects.
Colin overlooked a torn glove during an equipment check. Yuri used the glove during a power outage and suffered burns when the glove failed after a fall. The university could still face liability even though the precise sequence of outage, fall, and leakage was unforeseen.
Summit Gas delayed repair of a known gas leak. Chase illegally connected a grill that ignited the gas. The court could determine as a matter of law whether the evidence permitted reasonable jurors to differ on whether the leak was a substantial factor in Marion's injuries.
Two trucks with defective brakes struck Silas's car after a rockslide. Video evidence left uncertainty over which truck caused specific fractures. The jury could decide whether each company's conduct was a substantial factor and how to apportion the indivisible paralysis.
A broker misrepresented loan terms to Amina. She relied on the statements and proceeded with construction financing that later caused pecuniary loss. The broker could be liable if her reliance was a substantial factor in choosing the transaction that produced the loss.
The substantial-factor test permits liability when negligent conduct actively contributes to harm even if another independent force would have produced the same result. But-for causation is not required when two forces each suffice on their own.
Supporting sources
The court decides whether the evidence creates a jury issue on the substantial-factor question. The jury decides the issue only when reasonable minds could differ on the facts.
Supporting sources
No. Once conduct is found to be a substantial factor, liability is not avoided merely because the actor did not foresee the extent or precise manner of the harm.
Supporting sources
Yes. When multiple tortious acts produce indivisible harm, each actor whose conduct is a substantial factor may be held liable for the entire harm.
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The plaintiff must show protected speech was a substantial or motivating factor in the adverse action. The government then must prove by a preponderance that the same decision would have been reached without the protected conduct.
Supporting sources
…the jury that the motive element could be satisfied by showing that “a person’s actual or perceived religion was a significant motivating factor for a [d]efendant’s action” “even if he or she had other reasons for doing what he or she did as well.” In taking issue with this instruction, the defendants argue that the phrase “because…