Negligence - Cause in Fact

“But-for” Test

The defendant’s conduct is a factual cause of the harm if the injury would not have occurred but for the defendant’s act or omission

Multiple tortfeasors

The but-for test may not work when:

• multiple tortfeasors are involved and it can’t be said that the defendant’s conduct was required to produce the harm;

• There are multiple possible causes but the plaintiff cannot identify which defendant actually caused the harm;

• Negligent medical misdiagnosis increased the risk of death, but the plaintiff likely would have died even with a proper diagnosis

Substantial Factor test

• Used when but-for causation does not wor because two or more defendants caused an indivisible injury

• Test is whether the defendant’s tortious conduct was a substantial factor in causing the plaintiff’s harm

Concurrent tortfeasors

When tortious acts of 2 or more defendants cause an indivisible injury to the plaintiff, the defendants are jointly and severally liable

Alternative Causation

If plaintiffs harm was caused by

• a small number of defendants

• each person’s conduct was tortious

• all present before court

Court may shift burden of proof to defendant to prove that his conduct was not the cause in fact of the plaintiff’s harm

Acting in Concert

applies when two or more defendants act together under a common plan or design

If any defendant’s tortious act causes harm, all defendants are jointly and severally liable (ex: drag race)

Loss of Chance

applies in medical malpractice when a doctor’s negligent misdiagnosis reduces a patient’s chance of survival

If patient’s pre-negligence chance of survival was below 50%, plaintiff can’t satisfy but-for causation—> in majority of jurisdictions, plaintiff may recover through this doctrine.

Plaintiff can recover [Total wrongful death damages x (% chance of survival before negligence - % after negligence)

Causal Linkage

Even if defendant’s conduct is a but-for cause, liability may be denied if the conduct did not increase the probability of the type of harm that occurred

(wagon mound 1; oil spill - fire was not a forseeable result)