Causation

P bears the burden of proving factual and legal causation (that D’s acts contributed in a real or material way to the harm to P) on the balance of probabilities (OBP) (WA s 52).

1. Proof by inference (that the circumstances give rise to an inference that is more probable than not) is acceptable to courts here (Holloway v McFeeters).

[Note each type of harm to P] Each must be considered separately to decide if there is causation.

Factual causation

To prove factual causation, the negligence must have been a necessary condition of the occurrence of the harm (WA s 51(1)(b)).

This requires application of the ‘but for’ test: there will be factual causation if, OBP, the P’s injury would not have occurred but for the D’s breach of DOC (Barnett v Chelsea & Kensington Hospital).

1. Evidence of what P would subjectively have done if not for D’s negligence will be considered by the court if relevant (WA s 51(3))

   1. Concerns what P (not a reasonable person) would subjectively have done.

      1. Chappel v Hart: court accepted that P would have delayed the operation and avoided harm

2. The ‘but for’ test is insufficient alone and must be applied using common sense and value judgments (March v Stramare).

3. Where the link between D’s negligence and the harm to P is limited to D’s act putting P into the spatial and temporal position where P encounters the hazard, D’s negligence is not a legal cause of the injury (Chappel v Hart, March v Stramare).

[Note prima facie result under the but for test]

However, if there are multiple sufficient causes, such that the test is not satisfied, the court may nevertheless impose responsibility for factual causation on D where appropriate (WA s 51(2)).

1. The court may decide factual causation is proven if D’s negligence materially contributes to P’s harm but cannot be shown to have been a necessary condition of its occurrence (Strong v Woolworths).

[Note if appropriate eg if two people caused a death together]

Increased risk

If it is unclear that D’s act was a necessary condition of D’s harm, but it made the harm more likely, a court may apply the doctrine of increased risk, though it is very uncertain in Australia.

Arguments for increased risk

In Amaca v Booth, the High Court found that where a cumulative effect of exposure to something is known to cause illness, and D was responsible for P’s substantial exposure to that thing, it will be deemed that D has materially contributed to P’s harm if the illness does arise; and this is enough to show factual causation.

[Note whether this applies to the circumstances and whether factual causation would be shown]

P may argue that under WA s 51(2), even where something cannot be proved to be a necessary condition of harm, the court may deem it as such. Arguably then an Australian court should apply the House of Lords case of Fairchild v Glenhaven, which held that injustice to the D is outweighed by policy reasons in favour of compensating the P.

P can argue that the similar test propounded by Kirby and Gaudron JJ in Chappel v Hart should apply. They held that if the P shows

• the D breached the DOC,

• the breach increased the risk that the P would suffer a particular kind of injury, and

• the P did in fact suffer an injury of that kind,

then a prima facie case of causation is established. This means the burden of disproving factual causation is shifted to D.

[Apply this test and decide whether D can show there is no factual causation]

Arguments against increased risk

However, D may argue increased risk does not apply in Victoria, because

1. Per WA s 52, the P must prove causation OBP, and if increased risk is allowed, the standard of proof is lowered.

   1. Kiefel J in Tabet v Gett indicated that the standard of proof could not be lowered and indicated accordingly that increased risk would not apply

2. Amaca v Ellis did not consider increased risk where it could in fact have been applied, suggesting increased risk does not apply in Australia.

D may also argue if it does apply, it...

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