Learning Outcomes
After reading this article, you will be able to identify and apply the rules governing causation in negligence for MBE purposes. You will distinguish between factual causation and proximate cause, analyze situations involving multiple causes or defendants, and recognize how legal standards determine liability. You will be equipped to answer MBE questions on causation with confidence.
MBE Syllabus
For MBE, you are required to understand the principles of causation in negligence. This includes both factual and legal (proximate) causation, as well as the treatment of cases involving multiple causes or defendants. You should be able to:
- Distinguish between factual causation ("but for" and "substantial factor" tests) and proximate cause.
- Apply the rules for causation where there are multiple sufficient or indeterminate causes.
- Recognize the effect of intervening and superseding events on liability.
- Analyze scenarios involving joint tortfeasors and alternative liability.
- Understand the "eggshell plaintiff" rule and its impact on damages.
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 test is most commonly used to establish factual causation in negligence?
- Substantial factor test
- "But for" test
- Foreseeability test
- Last clear chance doctrine
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If two defendants independently cause the same harm and either act alone would have been sufficient, what is the standard for causation?
- Both are liable only if acting in concert
- Neither is liable because the harm would have occurred anyway
- Each is liable if their conduct was a substantial factor in causing the harm
- Only the first actor is liable
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An unforeseeable criminal act by a third party occurs after a defendant’s negligence. Is the original defendant generally liable for the resulting harm?
- Yes, always
- No, because it is a superseding cause
- Yes, if the defendant was reckless
- No, unless the defendant intended the harm
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Under the "eggshell plaintiff" rule, a defendant:
- Is liable only for foreseeable injuries
- Is liable for all injuries caused, even if the extent is unforeseeable
- Is not liable if the plaintiff had a pre-existing condition
- Can reduce damages if the plaintiff is unusually vulnerable
Introduction
Causation is a core element of negligence. To recover, a plaintiff must prove that the defendant’s breach both factually and legally caused the harm. This article explains how to analyze causation for MBE questions, including the difference between factual causation and proximate cause, and how to handle complex situations with multiple causes or defendants.
Factual Causation: The "But For" Test
Factual causation asks whether the harm would have occurred "but for" the defendant’s breach. If the injury would not have happened without the defendant’s conduct, factual causation is established.
Key Term: Factual Causation The requirement that the defendant’s breach was a necessary condition for the plaintiff’s harm; usually tested by asking if the harm would have occurred "but for" the defendant’s act.
Substantial Factor Test and Multiple Sufficient Causes
When two or more independent acts would each have been sufficient to cause the harm, the "substantial factor" test is used. If each defendant’s conduct was a substantial factor in bringing about the injury, both are liable.
Key Term: Substantial Factor Test A standard used when multiple acts combine to cause harm; each act is a substantial factor if it alone would have been sufficient to produce the result.
Indeterminate Causes and Alternative Liability
If it is unclear which of several negligent defendants caused the harm, but all were negligent, the burden shifts to the defendants to prove they did not cause the injury. If they cannot, all may be held jointly liable.
Key Term: Alternative Liability A doctrine that shifts the burden of proof to multiple negligent defendants when it is uncertain which one caused the plaintiff’s harm.
Proximate Cause: Legal Limitation on Liability
Proximate cause limits liability to those harms that are a foreseeable result of the defendant’s conduct. Even if factual causation is present, a defendant is not liable for injuries that are too remote or result from extraordinary, unforeseeable events.
Key Term: Proximate Cause The legal requirement that the harm must be a foreseeable consequence of the defendant’s breach, not too remote or extraordinary.
Intervening and Superseding Causes
An intervening event is one that occurs after the defendant’s act and contributes to the harm. If the intervening event is unforeseeable and breaks the chain of causation, it is called a superseding cause and relieves the original defendant of liability.
Key Term: Superseding Cause An unforeseeable intervening event that breaks the chain of causation, relieving the original defendant of liability for subsequent harm.
The "Eggshell Plaintiff" Rule
A defendant takes the plaintiff as found. If the plaintiff suffers greater harm than expected due to a pre-existing condition, the defendant is fully liable for all resulting injuries.
Key Term: Eggshell Plaintiff Rule The principle that a defendant is liable for the full extent of the plaintiff’s injury, even if the injury is more severe than what was foreseeable.
Multiple Defendants: Joint and Several Liability
When multiple defendants combine to cause an indivisible injury, each is jointly and severally liable for the entire harm. The plaintiff may recover the full amount from any one defendant.
Key Term: Joint and Several Liability The rule that each of multiple defendants responsible for an indivisible harm is liable for the entire amount, allowing the plaintiff to recover from any one.
Worked Example 1.1
A factory negligently emits toxic fumes. Two nearby residents, A and B, both develop respiratory illness. Medical evidence cannot determine whether A’s illness was caused by the factory or by a different nearby plant, which was also negligent. Both plants are sued.
Answer: Because both defendants were negligent and it is unclear which caused the harm, the burden shifts to the defendants to prove they did not cause A’s illness. If neither can do so, both may be held jointly liable under alternative liability.
Worked Example 1.2
Two drivers, X and Y, independently drive negligently and each crashes into a parked car at the same time, causing it to be destroyed. Either collision alone would have totaled the car.
Answer: Both X and Y are liable. Each act was a substantial factor in causing the harm, so both are responsible for the full damage.
Worked Example 1.3
A defendant leaves a pit uncovered. Later, a third party pushes the plaintiff into the pit. Is the original defendant liable for the plaintiff’s injuries?
Answer: If the third party’s act was a foreseeable result of the defendant’s negligence (e.g., the area was known for rough behavior), the defendant remains liable. If the act was unforeseeable and extraordinary, it may be a superseding cause, relieving the defendant of liability.
Exam Warning
In MBE questions, do not confuse factual causation with proximate cause. A defendant may be the factual cause but not the proximate cause if the harm is unforeseeable or results from a superseding event.
Revision Tip
Always ask: Was the defendant’s breach a necessary condition for the harm? Was the harm a foreseeable result? Identify any intervening or superseding causes.
Key Point Checklist
This article has covered the following key knowledge points:
- Factual causation is usually established by the "but for" test.
- The substantial factor test applies when multiple sufficient causes exist.
- Alternative liability shifts the burden to defendants when the actual cause is indeterminate.
- Proximate cause limits liability to foreseeable harms.
- Superseding causes break the chain of causation and relieve liability.
- The eggshell plaintiff rule makes defendants liable for all resulting harm, even if unforeseeable in extent.
- Joint and several liability applies to indivisible injuries caused by multiple defendants.
Key Terms and Concepts
- Factual Causation
- Substantial Factor Test
- Alternative Liability
- Proximate Cause
- Superseding Cause
- Eggshell Plaintiff Rule
- Joint and Several Liability
