Once established that a health practitioner breached their duty of care by falling below the expected standard of professional behviour, the plaintiff must prove that the harm or loss suffered was caused by the defendant’s breach. That is, there must be a direct causal link between the wrong committed by the health practitioner and the harm suffered by the person claiming negligence.
Causation is frequently at issue in medical negligence cases.
Causation must be proven according to the civil burden of proof, which is on the balance of probabilities (that is, it is ‘more likely than not’ that the wrong caused the harm/loss). In this sense, the Court is concerned with probabilities and not possibilities.
The Court is also concerned with causation at law (and not philosophy or science), which is ultimately about liability (that is, holding someone financially responsible for another’s harm/loss). There are therefore legal tests that need to be satisfied.
Civil liability legislation in all states and territories of Australia addresses the issue of causation as involving two distinct inquiries:
1) factual causation which requires the determination of whether the breach of duty (or negligence) was ‘a necessary condition for the occurrence of harm'. If the answer is yes, the Court will proceed to the second inquiry:
2) scope of liability which entails consideration of whether it is appropriate for the scope of the negligent person’s liability to extend to the harm so caused. Here we will ask questions about whether anything else may have intervened to cause the patient’s harm and severed the chain of causation; or whether the damage suffered was too remote a consequence and could not have been foreseen. If either of these questions are answered positively (i.e. with a ‘yes’) then the claim will fail.
This type of inquiry will rely on evidence from, for example, experts who may support the causal link.