What is "causation"?

“Causation,” in a personal injury case, makes the crucial link between a person or company’s behavior and another person’s injury. Even if a defendant in a negligence case is horribly careless or reckless, he cannot be held liable for injuring the plaintiff unless his negligent behavior caused the injury.

In order to “cause” an injury, a particular action, condition, or thing does not have to be the sole reason the injury occurred. Rather, a particular cause only has to be a “substantial factor” in creating or worsening the injury.

In most torts cases, causation can be broken down into two different types: cause in fact and proximate cause. The cause in fact of an injury is the one that, if it had not happened, the injury would not have happened either. A court looking for a cause in fact asks, “If this event did not happen, would the plaintiff have been injured?”

If the court determines that a particular cause was the cause in fact of an injury, it then asks whether that same cause was also a proximate cause. Proximate cause asks whether the injury was foreseeable.Even if a defendant‘s action was the “but-for” cause of a plaintiff’s injury, the defendant may not be liable for damages if his action was so far removed from the injury that he could not have foreseen that his action would cause that kind of harm.

The famous torts case that explains the difference between cause in fact and proximate cause is Palsgraf v. Long Island Railroad Co. In this case, a man ran across a train platform to catch a train. He was carrying a package. As he approached the train, it began to move, so at the last second the man tried to leap aboard the train. As he was trying to get onto the train, two Long Island railroad guards, one on the train itself and one on the train platform, pushed and pulled the man, trying to make sure he landed securely on the train.

As the railroad guards jostled the man, he dropped his package, which happened to be full of fireworks. The fireworks exploded, panicking the crowd on the platform. A panicking crowd member pushed against a heavy set of scales. The scales fell over onto Mrs. Palsgraf, injuring her. Mrs. Palsgraf sued the railroad, claiming that the negligence of the railroad guards in pushing the man onto the train caused her injuries.

The court found that cause in fact existed, because if the package had not been dropped, its exploding contents would not have scared the bystander into pushing the scales so they fell on Mrs. Palsgraf. However, the court held that proximate cause did not exist, because there was no way that the railroad guards could have foreseen that Mrs. Palsgraf would be hit by falling scales if they pushed a man trying to get onto the train at the opposite end of the train platform.

In a standard negligence case, proving causation is only one step in proving that a defendant is liable for a plaintiff’s injuries. Proving a negligence case also requires evidence that the defendant had a duty of care to the plaintiff, that he breached that duty, and that the breach caused the plaintiff’s injuries, which can be righted by the defendant paying damages to the plaintiff.

In some types of personal injury cases, however, causation is the center of the case. For instance, in a strict liability case like those involving products liability or ultrahazardous activities, the plaintiff only needs to prove that the harmful behavior or product caused her injuries.