What's Causation in a Personal Injury Case?Many personal injury claims are based on the law of negligence. This legal theory revolves around a person’s unreasonable behavior that leads to another person’s injury.

Under Kentucky law, an injured person must prove four elements to establish the defendant’s negligence:

  1. The defendant owed a duty to the plaintiff.
  2. The defendant breached that duty.
  3. The breach caused the plaintiff’s injury.
  4. The plaintiff suffered an injury and can prove it.

The third element is called “causation.”


Under Kentucky law, a plaintiff must prove the following to establish causation:

  1. The defendant’s negligent conduct was a substantial factor in bringing about the plaintiff’s harm; and
  2. No rule of law exists that relieves the defendant from liability due to the manner in which their negligence resulted in the harm.

These two requirements may sound straightforward, but they can quickly become complicated, as shown by the following examples.

Substantial Factor

A plaintiff must show that the defendant’s behavior was a substantial factor in causing their injury or harm to prove causation. A substantial factor is one that contributes materially to the cause of an injury. An action is material if it continues until the moment of injury.

A court or jury will consider several factors to determine whether the defendant’s acts or omissions were the substantial cause of a plaintiff’s injuries, including:

  1. Other factors that contribute to producing the harm
  2. Whether the defendant’s conduct resulted in a force that remained active up to the time of the harm, or the conduct was harmless
  3. The time between the defendant’s conduct and harm

For example, say a defendant runs a red light and hits the plaintiff’s car, causing whiplash. The defendant’s running the red light was a substantial factor in causing the plaintiff’s whiplash. It was material because it caused and continued up until the moment of the cause of the plaintiff’s injury: the crash.

Rule of Law

Despite the terminology, rule of law here refers to “substantive policy rules which limit responsibility for a negligent act.” Traditionally, this has been referred to as “proximate cause.” Perhaps the most common way to think about public policy limitations is in terms of foreseeability.

Courts will not hold a defendant liable for every harm a plaintiff suffers — only the ones that are a foreseeable result of the defendant’s conduct. This rule is concerned with fairness. It seeks to limit the chain of causation to actions that result in foreseeable injuries to foreseeable plaintiffs. In other words, an action cannot be too remote and still satisfy this proximate cause element.

Palsgraf – an Example

The best way to understand this is with another example. For that, we’ll use the case of Palsgraf v. Long Island, one of the most famous cases in negligence law. In Palsgraf, the plaintiff was standing on a railroad platform waiting for a train. A train soon approached, and another passenger several yards away ran to board it. He stumbled, though, and two nearby railroad employees dashed over to help the man.

The prospective passenger dropped a wrapped package, which contained explosives, in the process. When the package hit the ground, it caused an explosion. The explosion knocked down scales on the other side of the platform, which fell on the plaintiff.

The plaintiff sued the railroad company and established that the two railroad employees acted negligently. But she could not prove causation. The court found that it was not foreseeable that the negligent conduct of two railroad employees trying to prevent a person from falling several yards away from the plaintiff would harm her.

In other words, she was not a foreseeable plaintiff. It was foreseeable that the railroad employees might injure themselves or the other passenger when they tried to prevent him from falling. It was not foreseeable that their conduct would result in an explosion that injured a passenger on the other side of the platform. Therefore, the court ruled there was no causation.

Your Causation Law Firm

Matthew Minner, a Lexington, KY personal injury attorneyIf you’re injured in an accident caused by a negligent person, you have a lot on your mind. You’re likely dealing with medical bills and worrying about who’s going to pay for them all – the last thing on your mind is the question of causation.

Our experienced and dedicated personal injury lawyers At Minner Vines Injury Lawyers, PLLC can help you file the appropriate lawsuit to seek your damages, and part of this includes providing the needed evidence to establish causation.