Learning Outcomes
After reading this article, you will be able to identify when an intervening act becomes a superseding cause that breaks the chain of proximate causation in negligence. You will understand the distinction between foreseeable and unforeseeable intervening events, apply the correct legal standards, and analyze whether a defendant remains liable for harm following subsequent acts or events. This will enable you to answer MBE questions on proximate cause and superseding causes with confidence.
MBE Syllabus
For MBE, you are required to understand how intervening acts affect a defendant’s liability in negligence. This article covers:
- The definition and role of superseding causes in negligence.
- The difference between intervening and superseding causes.
- The foreseeability test for intervening events.
- The effect of criminal acts, intentional torts, and acts of God on proximate cause.
- How to determine when a defendant is relieved from liability due to a superseding cause.
Test Your Knowledge
Attempt these questions before reading this article. If you find some difficult or cannot remember the answers, remember to look more closely at that area during your revision.
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Which of the following is most likely to be considered a superseding cause that relieves a defendant of liability?
- (A) A foreseeable act of negligence by a third party.
- (B) An unforeseeable criminal act by a third party.
- (C) A foreseeable reaction by the plaintiff to the defendant’s conduct.
- (D) A subsequent medical error that aggravates the plaintiff’s injury.
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If an intervening act is deemed foreseeable, what is the effect on the original defendant’s liability?
- (A) The defendant is always relieved of liability.
- (B) The defendant remains liable for the harm.
- (C) The intervening act is always a superseding cause.
- (D) The plaintiff cannot recover from anyone.
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Which of the following is NOT typically a superseding cause?
- (A) Grossly negligent medical treatment.
- (B) Ordinary negligence by a rescuer.
- (C) A natural event that was foreseeable.
- (D) A subsequent disease resulting from the original injury.
Introduction
In negligence, a defendant is liable only for harm that is proximately caused by their conduct. Sometimes, after the defendant’s act, another event or act occurs and contributes to the plaintiff’s injury. Whether the defendant remains liable depends on whether this later event is a mere intervening cause or a superseding cause that breaks the chain of causation.
Key Term: Intervening Cause An event or act that occurs after the defendant’s negligent conduct and contributes to the plaintiff’s harm.
Key Term: Superseding Cause An intervening act or event that is so unforeseeable and independent that it breaks the chain of proximate causation, relieving the original defendant of liability.
Intervening vs. Superseding Causes
An intervening cause is any event that happens after the defendant’s act and contributes to the result. Not all intervening causes relieve the defendant of liability. Only those that are deemed superseding—because they are unforeseeable and independent—will cut off the defendant’s responsibility.
The Foreseeability Test
The key question is whether the intervening act was foreseeable. If the intervening event was a normal or foreseeable result of the defendant’s negligence, it will not be a superseding cause. The defendant remains liable for the harm.
If the intervening act is extraordinary, highly unusual, or not reasonably anticipated, it may be a superseding cause. In that case, the defendant is not liable for the harm that follows.
Key Term: Foreseeability The likelihood that a reasonable person in the defendant’s position would have anticipated the intervening act or event as a possible result of their conduct.
Types of Intervening Events
Some intervening acts are almost always considered foreseeable and thus not superseding:
- Ordinary negligence by rescuers or third parties.
- Efforts to protect persons or property endangered by the defendant’s conduct.
- Subsequent medical treatment (unless grossly negligent).
- Plaintiff’s reaction to the danger created by the defendant.
Other intervening acts are generally unforeseeable and may be superseding:
- Criminal acts or intentional torts by third parties (unless the defendant’s conduct made such acts likely).
- Extraordinary acts of nature (acts of God) that are not reasonably predictable.
Criminal Acts and Intentional Torts
If a third party’s criminal act or intentional tort is not foreseeable, it is usually a superseding cause. However, if the defendant’s conduct created a situation where such acts were likely (e.g., leaving keys in an unlocked car in a high-crime area), the criminal act may be deemed foreseeable, and the defendant may remain liable.
Acts of God and Natural Events
Natural events, such as storms or earthquakes, are superseding causes only if they are so unusual that no reasonable person could have anticipated them. If the event was foreseeable, the defendant remains liable.
Medical Malpractice and Subsequent Harm
Subsequent medical treatment is typically foreseeable, even if negligent, and does not break the chain of causation. Only grossly negligent or intentional medical errors may be considered superseding.
Worked Example 1.1
A driver negligently leaves a car blocking a lane on a busy street. Later, a thief steals the car and, while fleeing, hits a pedestrian. Is the driver liable for the pedestrian’s injuries?
Answer: If car thefts are common in the area and the driver’s conduct made theft likely (e.g., keys left in the ignition), the theft may be foreseeable and not a superseding cause. The driver remains liable. If car thefts are rare and the theft was highly unusual, the theft may be a superseding cause, relieving the driver of liability.
Worked Example 1.2
A store owner negligently fails to repair a broken step. A customer trips, falls, and is taken to the hospital. The doctor commits an ordinary error in treatment, worsening the injury. Is the store owner liable for the aggravated harm?
Answer: Yes. Ordinary medical negligence is foreseeable and does not break the chain of causation. The store owner remains liable for the full extent of the injury.
Worked Example 1.3
A landlord negligently fails to fix a broken lock. A burglar enters and assaults a tenant. Is the landlord liable for the tenant’s injuries?
Answer: If the area is known for break-ins and the landlord’s negligence made criminal entry likely, the assault may be foreseeable. The landlord may be liable. If violent crime was highly unusual and not reasonably anticipated, the criminal act may be a superseding cause, relieving the landlord of liability.
Exam Warning
In MBE questions, do not assume every criminal act or act of God is a superseding cause. Always analyze whether the event was foreseeable in light of the defendant’s conduct and the circumstances.
Revision Tip
When analyzing proximate cause, always ask: Was the intervening act a normal or foreseeable result of the defendant’s negligence? If so, the defendant remains liable.
Key Point Checklist
This article has covered the following key knowledge points:
- A superseding cause is an unforeseeable, independent intervening act that breaks the chain of proximate causation.
- Foreseeable intervening acts do not relieve the defendant of liability; only unforeseeable, extraordinary events may be superseding.
- Criminal acts, intentional torts, and acts of God are superseding causes only if unforeseeable.
- Ordinary negligence by rescuers or medical providers is usually foreseeable and not superseding.
- The defendant remains liable for harm if the intervening act was a foreseeable result of their negligence.
Key Terms and Concepts
- Intervening Cause
- Superseding Cause
- Foreseeability
