4.3 Problems in proving causation
4.3.1 The problem of multiple causes
The problem of proving a causal link between the defendant’s negligent act and the damage is always made more difficult where there is the possibility of more than one cause. In such instances the court is forced into the position of trying to determine which of the possibilities is the actual cause of the damage suffered. Very often the court will find that it is impossible to do this with accuracy and the claimant may be left without compensation at all.
CASE EXAMPLE
Wilsher v Essex Area Health Authority [1986] 3 All ER 801 CA
Here a baby after being delivered was given excess oxygen as a result of the admitted error of the doctor and the baby then suffered blindness through retrolental fibroplasia. The House of Lords identified that the excess oxygen was just one of six possible causes of the condition and therefore it could not be said to fall squarely within the risk created by the defendants. The court would not impose liability on the defendant in these circumstances although this seems very unfair.
The difficulty of identifying precise cause means that the case law is often inconsistent.
The risk then is that the decision will appear on the surface to be unfair to the claimant.
This again is all too common where the chance of recovery may have been lost through negligence in medical treatment or diagnosis.
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CASE EXAMPLE
Hotson v East Berkshire Area Health Authority [1987] 1 All ER 210
A young boy suffered a fractured hip when he fell out of a tree. The hospital negligently failed to make a correct early diagnosis so that he later developed avascular necrosis, a deformity of the hip. Expert evidence confirmed that he would have had a 75 per cent chance of the deformity even without the failure to diagnose promptly. On this basis the trial judge, and later the Court of Appeal, awarded him 25 per cent of the damages they would have considered appropriate for the condition for the loss of a chance of recovery. The trial judge commented that the hospital had translated the probability of the disability developing into a certainty by negligence in their failure to diagnose. However, the House of Lords allowed the Health Authority’s appeal and would not consider the slim chance of recovery an issue of causation.
Lord Ackner summed up the issue of causation in the case quite succinctly:
JUDGMENT
‘the deformed hip . . . was not caused by the admitted breach by the defendants . . . but was caused by the separation of the left femoral epiphysis when he fell . . . I have sought to stress that this case was a relatively simple case concerned with the proof of causation, upon which the plaintiff failed, because he was unable to prove on the balance of probabilities that his deformed hip was caused by the defendant’s breach of duty in delaying over a period of five days a proper diagnosis and treatment.’
However unfair the position of the House of Lords may appear there is nevertheless no disputing its legal logic.
QUOTATION
‘The emotive speech and obvious feelings for a “lost chance” plaintiff must not let us colour or obscure the real issue – the existence of an “evidentiary gap”. Proof of causation should not be accepted on anything less than the balance of probabilities, as is common with all civil actions.’
T Hill ‘A lost chance for compensation in the tort of negligence by the House of Lords’
[1991] 54 MLR 511 The House of Lords has had a more recent opportunity to review the law on ‘loss of a chance’.
CASE EXAMPLE
Gregg v Scott [2005] UKHL 2; [2005] 2 WLR 268
The claimant was concerned about a lump under his arm but his GP failed to refer him to a hos- pital for tests, dismissing the lump as harmless fatty tissue. When the claimant saw another GP nine months later, by which time he was in considerable pain, he was referred to hospital for tests and cancer of the lymph glands was diagnosed which it was established had spread consider- ably during the delay. The claimant argued negligence on the part of the original doctor and it was shown that if his condition had been diagnosed on the first visit and treatment had started at that point he would have had a 42 per cent chance of being alive and disease free in ten years, whereas as a result of the delay in treatment his chances of being alive and disease free after ten years had reduced to 25 per cent. The House of Lords, on a split decision 3:2, was unwilling to depart from the principle in Hotson by awarding the claimant a proportion of what he would have recovered if the doctor’s negligence had in fact caused his premature death. Interestingly the House added that, had the claimant sought damages for the pain and suffering experienced during the delay in treatment these might have been awarded.
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The majority judges and the dissenting judges were clearly unconvinced by each other’s irreconcilable reasoning.
Lord Hoffmann, delivering the leading judgment held:
JUDGMENT
‘Academic writers have suggested that in cases of clinical negligence, the need to prove causa- tion is too restrictive . . . In the present case it is urged that Mr Gregg has suffered a wrong and ought to have a remedy [and that] the exceptional rule in Fairchild should be generalised and damages awarded in all cases in which the defendant may have caused an injury and has increased the likelihood of the injury . . . It should be first noted that adopting such a rule would involve abandoning a good deal of authority.’
Lord Nicholls dissenting, on the other hand stated:
JUDGMENT
‘Given the uncertainty of outcome, the appropriate characterisation of a patient’s loss in this type of case must surely be that it comprises the loss of a chance of a favourable outcome, rather than the loss of the outcome itself. Justice so requires . . . And this analysis of a patient’s loss accords with the purpose of the legal duty . . . to promote the patient’s prospects of recov- ery by exercising due skill and care in diagnosing and treating the patient’s condition. This approach also achieves a basic object of the law of tort. The common law imposes duties and seeks to provide appropriate remedies in the event of a breach of duty. If negligent diagnosis . . . diminishes a patient’s prospects of recovery, a law which does not recognise this as a wrong calling for redress would be seriously deficient . . .’
A claim for loss of life expectancy may give rise to compensation.
CASE EXAMPLE
JD v Mather [2012] EWCH 3063
A claimant with a malignant melanoma was not diagnosed by his doctor for six months after it should have been. In fact his original chances of surviving ten years were under 50 per cent so he could not prove that he might have been cured. However, the tumour had developed into a worse category by the time it was diagnosed and since life expectancy for this category was three years less he was able to claim for three years’ loss of life expectancy.
Ultimately the legal justification for failing to provide a remedy in the ‘loss of a chance’
cases lies in the fact that the claimant’s arguments on causation rests on a possibility rather than a probability of harm occurring, and on a simple balance of probabilities test the claims fail.
The reverse possibility of course is that the court chooses to accept the chance of a causative link between the defendant’s acts and the damage. However, in this instance it may risk the possibility of unfairly penalising the defendant.
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CASE EXAMPLE
McGhee v National Coal Board [1973] 3 All ER 1008
Here the claimant worked in a brick kiln where he was exposed to brick dust, a possible cause of the dermatitis that he in fact contracted. The Board was not liable for exposure during working hours. They were held liable for materially increasing the risk of the claimant contract- ing the disease because of their failure to provide washing facilities, even though it could not be shown that he would have avoided the disease if there had been facilities. The reasoning of the court was that, since the employer was clearly negligent in failing to provide basic health and safety the burden should shift on to them to disprove the causal link. This type of test is clearly more advantageous to a claimant than the basic ‘but for’ test applied so rigidly in Hotson v East Berkshire AHA [1987] 1 All ER 210.
The problems that the courts have in determining cause are further added to in circum- stances where they are also asked to decide the possible outcomes of hypothetical situations.
CASE EXAMPLE
Bolitho v City and Hackney Health Authority [1997] 4 All ER 771
Here the doctor had been negligent in failing to attend a child with severe respiratory dif- ficulties despite the requests of the nursing staff for her attendance. The doctor claimed that this fact was irrelevant in relation to the cardiac arrest and eventual death of the child. Her argument was that, even if she had attended the child with the breathing difficulties she would not in any case have intubated and thus the same damage would have occurred and that there was responsible medical opinion that would support the practice in the circum- stances of the case. The House of Lords rejected the idea that the Bolam test should be applied to the issue of causation in order that the Health Authority should escape liability.
Nevertheless, there are occasions where the courts appear to take a pragmatic approach where proof of causation is difficult.
CASE EXAMPLE
Bonnington Castings Ltd v Wardlaw [1956] AC 613
The claimant contracted pneumoconiosis after years of working in dusty conditions and without adequate washing facilities. There were two principal causes of dust, the one requir- ing no extraction system and the other which did, but no extractor was provided. It was impossible to prove accurately which dust the claimant had inhaled most of. Since the dust which should have been extracted legally was at least a partial cause of his illness the court were prepared to award compensation.
The courts are also at times prepared to accept the chance of a causal connection with the damage or the chance of damage being avoided without the defendant’s negligent act or omission.
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CASE EXAMPLE
Stovold v Barlows, The Times, 30 October 1995
It was claimed that a house sale was lost through the negligence of the solicitors. The Court of Appeal felt that there was at least a 50 per cent chance that the deal would otherwise have gone through and so awarded half damages.
But equally courts have been prepared to place too much emphasis on a single cause out of a number of possibilities, leading to unfair treatment of the claimant.
CASE EXAMPLE
Fairchild v Glenhaven Funeral Services Ltd and others [2002] 1 WLR 1052, CA This case involved a number of appeals. The claimants suffered mesothelioma after exposure to asbestos dust over many years working for a number of different employees. The medical evidence identified that the inhaling of asbestos fibres was the cause of the disease. Neverthe- less, it was impossible to identify in which particular employment the disease was actually contracted. The Court of Appeal accepted that medical evidence could not identify a single cause of the disease, which might be caused by contact with even a single asbestos fibre, or may involve cumulative exposure to fibres. As a result the Court held that the precise employer responsible could not be identified and so the claim should be rejected. It is impossible to say with certainty how the disease begins, but it is possible to identify that prolonged exposure worsens the risk. It seems then that the Court of Appeal applied Wilsher v Essex AHA [1986]
3 All ER 801 inappropriately where McGhee v NCB [1973] 3 All ER 1008 might have been more fairly applied in the circumstances. The House of Lords has in any case subsequently reversed the Court of Appeal decision (see section 4.3.3).
The decision in the Court of Appeal inevitably led to criticism.
QUOTATION
‘The “single hit” theory that one asbestos fibre alone is capable of initiating mesothelioma has been the source of incalculable harm . . . The key point is that the “single hit” theory presup- poses a deterministic view which is not supported by science. It encourages a mindset much closer to criminal law – equating the “guilty” fibre with the knife or bullet which severs the victim’s aorta. Of course, lawyers, like most non- scientists, find it hard to resist reducing a complex process to an easily visualised analogy. But they must not forget that the notion of the “guilty” fibre has no basis in the epidemiological evidence . . . The counter- argument that it is unjust to impose liability upon those not responsible for the “guilty” fibre . . . overlooks the role of tort in deterring all negligent behaviour not simply that which can be shown to result in actual injury.’
C Miller, ‘Why the House of Lords must overturn the Fairchild decision’ (2002) 152 NLJ 319
Multiple causes can arise generally in one of two ways:
J the multiple causes are concurrent; or J the multiple causes are consecutive.
Inevitably the role of the court is to determine and apportion liability and the result may be different in either case.
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