Causation Lecture Notes

Causation

The ‘But For’ Test

• The lecture will cover three causation issues:

  • The ‘but for’ test

  • The material contribution to injury

  • The material contribution to risk (Fairchild enclave)

• Exceptions:

  • Loss of a chance

  • Failure to warn

  • Supervening or overtaken causes

Establishing a Claim of Negligence

• The elements needed to establish a claim of negligence:

  • Duty

  • Breach

  • Causation

  • Remoteness (Cause in law)

• Other considerations:

  • Pure Economic Loss

  • Psychiatric injury

  • Standard of care

  • Cause in Fact

  • Omissions

  • Defences

    • Contributory negligence

    • Volenti

    • Ex turpi

• Proving breach is also an important aspect.

Introduction to Causation

• Causation is the third ingredient of the tort of negligence and a requirement of all tort damage claims.

• Factual causation and legal causation (remoteness) are the two types of causation.

  • Factual causation: Describes whether the defendant's negligence played a legally sufficient role in bringing about the claimant's harm.

  • Legal causation (remoteness): Deals with whether the defendant ought to be held liable to pay damages for that harm.

• In negligence, one must show that it was the defendant’s breach, and not just their actions/inactions (omissions), that caused the claimant’s loss.

The Classic “But For” Test

• The “but for” test is the first step in establishing causation.

• The question is: Would the claimant’s harm have happened but for the defendant’s breach?

• Case examples:

  • Barnett v Chelsea and Kensington Hospital [1969] QB 428

  • McWilliams v Sir William Arrol & Co Ltd [1962] 1 WLR 295: The defendant failed to provide a safety-belt for the employee (claimant), who fell to his death.

Applying the But-For Test

• The onus is on the claimant to prove causation on the balance of probabilities: 50% +

• Any cause is assessed as being on the balance of probabilities: “51% = 100 %”

• Wilsher v Essex AHA [1986] 3 All ER 801: Several different agents were in play, any of which may have caused the claimant’s harm, and none of which surmounts the balance of probabilities threshold; thus, causation must fail.

The Wilsher Scenario

• The five possible causes of baby Wilsher’s blindness:

  • Super-saturation of oxygen within the first 30 hours of the claimant’s life via the doctor’s mistake

  • Hypercarbia (an innocent cause)

  • Intra-ventricular haemorrhage (an innocent cause)

  • Apnoea – a common occurrence in newborn babies (an innocent cause)

  • Patent ductus arterisus (an innocent cause)

• Where the claimant was exposed to multiple causal agents that could give rise to the risk of harm, but which of those agents caused the claimant’s harm cannot be proven on the balance of probabilities, then causation must fail.

Difficulties with the “But For” Test

• The “but for” test has some difficulties, which are usually circumvented by the courts applying policy considerations.

• Situations, where the “but for” test does not work:

1. Over-determined causation

2. Loss of a chance

3. Failure to warn

4. Supervening causes/ intervening acts

5. Omissions

Over-Determined Causation

Introduction to Over-Determined Causation

• What happens where two or more tortfeasors commit a tort that would independently be sufficient to cause the claimant’s harm?

• The “but for” test would absolve both tortfeasors of liability!

• Over-determined causation has two categories:

1. Simultaneous causes

2. Successive causes

Simultaneous Causes

• Two or more tortfeasors commit a tort, at the same time, that would be independently sufficient to cause the claimant’s harm.

• Case example:
  *Hill v New River Co (1865) 6B & S 1008

Successive Causes

• Two or more tortfeasors commit a tort, one after the other, that would be independently sufficient to cause the claimant’s harm.

• There has to be a first and second tortfeasor.

• The second tortfeasor’s actions will be considered an intervening act that breaks the chain of causation with the first tortfeasor, unless the second tortfeasor’s actions are a natural and probable consequence of the first tortfeasor’s negligence.

• Case example:
  *Performance Cars Ltd v Abraham [1962] 1 QB 33

The Material Contribution Test

• Where the “but for” test fails to provide a remedy, policy considerations must be applied.

• One such policy consideration is the material contribution test:

  • Where the defendant’s breach makes a material contribution to the claimant’s harm, the defendant will be liable in negligence.

  • “Material” means more than negligible or minimal.

• The material contribution test is applicable in over-determined causation cases.

• Case examples:
  *Bonnington Castings Ltd v Wardlaw [1956] AC 613
  *Holtby v Brigham & Cowan (Hull) Ltd [2000] 3 All ER 421

The Fairchild Enclave

• What happens where the claimant is negligently exposed to the same agent by multiple defendants, all of which could have independently caused the claimant’s harm, but proving which defendant actually caused the harm is impossible?

• The House of Lords circumvented the “but for” test in Fairchild v Glenhaven Funeral Services Ltd [2003] 1 AC 32.

• Where the claimant is negligently exposed to the same agent by multiple defendants, all of which could have independently

caused the claimant’s harm, the claimant must prove that each defendant materially increased the risk of the claimant contracting the disease.