“If the common law is to retain its legitimacy it must remain capable of development. It must recognise the great advances made in medical knowledge and skills. It must recognise also the medical uncertainties which still exist. The law must strive to achieve a result which is fair to both parties in present-day conditions.”
(per Lord Nicholls in Gregg v Scott [2005] UKHL 2, paragraph 45)

Introduction

While the “but for” test had worked well in proving causation in clinical negligence for most of the cases for many years, there had been “…injustice in a common form type of medical negligence case. Some believe a remedy is essential and that a principled ground for providing an appropiate remedy can be found.” as described by Lord Nicholls in Gregg v Scott . The court had shown efforts to right wrongs and to produce “fair results” as examplified in Fairchild v Glenhaven funeral Services Ltd and Chester v Afshar . However, this piecemeal fashion of development of the law was best described by Lord Justice Brooke in his speech to the Medico-Legal Society, “…good quality law reform has to hang around waiting for parliamentary time year after year, and the judges are having to use chewing gum and Elastoplast and sticky plaster to try and find solutions to the problems this creates.”

The quote

The quote was said by Lord Nicholls in Gregg v Scott. He was one of the two minority who advocated the development of law in this case so as to do justice to the claimant. However the majority three called a halt to the development of law in the area of causation in clinical negligence, and a pause (though not an end) to the “loss of chance” claims.
Mr. Gregg was misdiagnosed by Dr. Scott to have lipoma at the axilla in November 1994.He was in fact suffering from non-Hodgkin’s lymphoma, which was only found out by another doctor in August 1995, nine month after his first consultation with Dr. Scott. Expert opinion pointed out that his chance of recovery, as defined by ten year survival, had been decreased from 42% to 27%. His claim for damage failed for causation because his chance for 10 year survival was less than even in any sense. His claim for “loss of chance” of better outcome was rejected by the court of first instance and then by the Court of Appeal. The main issue before the lawlords was “should this House introduce into the law of clinical negligence the right of a patient who has suffered an adverse event to rcover damages for the loss of a chance of a more favorable outcome?” By a near majority of three to two, the appeal was dismissed.

Legal principles in proving causation in clinical negligence claims:

1. The “but for” test. Causation would be proved if without the defendant’s negligent act, the claimant’s loss would not have occurred . The classical case referred to was Barnett v Chelsea & Kensington Hospital Management Committee .

2. The civil standard of proof. The claimant needs to prove, on a balance of probabilities, that the loss was more probable than not to be caused by the defendant’s negligent act.

3. The all-or-nothing approach. The claimant can get full damage if the above two criteria could be established. Otherwise, he would get nothing.

4. The burden of proof be on the claimant.

The problems of the legal principles in proofing casusation and the development

1. The “but for” test and the balance of probabilities

To prove causation by passing the “but for” test on the balance of probabilities had worked well in most cases. However in cases with “factual uncertainty”, the claimant may have an impossible burden of proving causation on the balance of probabilities. These are mainly cases with multiple causes and cases involving “loss of chance” as the head of damage. The result was that wrongs were not righted and some of the doctors’ duties became hollow ones.
Multiple causes
In the case of two simultaneous wrongs to the claimant, each of which would have been sufficient to cause the damage, the test produces the ludicrous conclusion that neither wrong caused the harm . The court had tried to overcome the fatual uncertainties and evidential gap of multiple causes by the drawing of inference.
In Bonnington Castings Ltd v Wardlaw , The House of Lords drew an inference of fact that the “guilty dust” had materially contributed to the damage and the employers were liable for the full extent of the loss. And anything which did not fall within the principle de minimis non curat lex would constitute a material contribution.
In McGhee v National Coal Board , the court took one more step forward by drawing an inference that a “material increase in the risk” as equivalent to a “material contribution to the damage”. The tradition “but for” test or even the “material contribution” test could not be passed because of the uncertainty of the actual cause by medical opinion.
The development was temporarily called to a halt by the House of Lords in Wilsher v Essex Area Health Authority . The House of Lords distinguished the case from Mc Ghee that a failure to take preventive measures against one out of five possible causes was no evidence as to which of those five caused the injury. They also held that Mc Ghee did not establish any new principle of law.
However, the interpretation of Mc Ghee in Wilsher was not accepted by the House of Lords in Fairchild v Glenhaven Funeral Services Ltd . The Court of Appeal applied Wisher and and held that the claimant failed to establish causation and a finding for the claimants would be unjust to the defendants because it could impose liability for the whole of an insidious disease on an employer with whom the claimant was employed for quite a short time in a long working life. The House of Lords revered the decision on the basis that in the special circumstances of this type of case, there should be a relaxation of the normal “but for” test. They ruled that there was new principle in Mc Ghee.
Another high-water mark was from the decision of the House of Lords in Chester v Afshar . Despite the claimant failed the accepted principle of causation, the House of Lords appled Fairchild and held that the test of causation was satisfied in the case.

Loss of a chance
For cases with natural poor outcome of less than even chance of success to start with, it was impossible to prove causation by the negligent act of the defendant because the unfavorable outcome was more probable to happen than not anyway. Another approach for these problems of factual uncertainty was the loss of chance approach: the claimant treated the loss of the chance of attaining a favorable outcome as an actionable damage. However this argument had never succeeded in clinical negligent claims.
In Kenyon v Bell , the court adopted the rule that only where the chances were over 50%, the plaintiff could recover full damages on the basis that causation was proved on the balance of probabilities. It was not achieved in that case.
In Hotson v East Berkshire Health Authority , the trial judge awarded 25% of the total damage to the claimant and this was affirmed by the Court of Appeal: “As matter of common sense, it is unjust that there should be no liability for failure to treat a patient, simply because the chances of a successful cure by that treaatment were less than 50 per cent….If this is the law, it is high time that it was changed, assuming that this court has power to do so.” The House of Lords reversed the decision and held that the claimant had failed to prove causation by a balance of probabilities. They also held that there was in fact no chance to lose as the fate of the epiphasis had been determined at the fall. They distinguished Mc Ghee that in this case medical evidence positively indicated that it was more likely than not that the plaintiff’s disability resulted from the “innocent” cause and there was no place to draw an inference.The decision had been critised heavily to be “a decision of strking analytic poverty and legal cowardice. ” “The House of Lords steadfastly refused to answer the question counsel for both sides were begging it to answer: is loss of a chance compensable damage in the context of clincal negligence?”
In Gregg v Scott , Lord Nicholls could not accept the result of strict application of the “all or nothing, balance of probability application of the but for test”. He proposed that the “diminution in prospect” approach of assessing loss of chance be applied in cases concerning hypothetical past facts with medical uncertainty on what the outcome would have been. He classified facts into “past facts”, “future prospects” and “hypothetical past facts”. He quoted Lord Diplock in Mallett v McMongale that past facts were decided on the balance of probability, which future prospects call for an assessment of likelihood. For hypothetical past facts, he distinguished Hotson by classifying them into two cateogories depending on whether a patient’s condition at the time of the negligence does or does not give rise to significant medical uncertainty on what the outcome would have been in the absence of negligence . The “diminution in prospect” approach proposed to be applied in the latter type (the Gregg type) cases.
Lord Hope saw the loss of chance as consequential to the physical injury, “The fact that there was a physical injury has been proved on a balance of probabilities. So too has the fact that, in addition to pain and suffering, it caused a reduction in the prospect of a successful outcome. I would hold that, where these factors are present, the way is open for lossed which are consequential to the physical injury to be claimed too.”

The majority view in Gregg
Lord Hoffmann quoting Helen Reece , argued against the idea of uncertainty: “ the law regard the world as in principle bound by laws of causality….There is no inherent uncertainty about what caused something to happen in the past or about whether something which happened in past will cause something to happen in the future. Everything is determined by causality. What we lack is knowledge and the law deals with lack of knowledge by the concept of the burden of proof.”
Lord Phillips dismissed the claim in a practical point of view, “It is always likely to be much easier to resolve issues of causation on balance of probabilities than to identify in terms of percentage the effect that clinical negligence had on the chances of a favourable outcome….A robost test which produces rough justice may be preferable to a test that on occasion will be difficult, if not impossible, to apply with confidence in practice.”
Baroness Hale analysed the concept of a loss chance, “once a breach of duty has been shown, the recent decision of the New South Wales Court of Appeal in Rufo v Hesking illustrates how easy it may be to conclude that this has led to a reduction in the patient’s prospect of a favourable outcome….And common sense will ofter suggest that the chances of a better outcome would have been better if the doctor had done what he should have done….Reformulating the damage in this way could lead to some liability in almost every case,” and the practicability: “the expert evidence would have to be far more complex than it is at present….Recovery would be much less predictable both for claimants and for defendants’ liability insurers.”

Loss of chance in other areas of law
A comparison with decisions in other areas of law concerning a loss of chance as head of damage makes the cases in clinical negligence difficult to reconcile. Damages were compensated for cases with less than even chance prospect.
A loss of chance is recoverable in damage in contract. In Chaplin v Hicks , where a person is deprived of a right to belong to a limited class of competitors for a prize of value, the value of his loss of the opportunity of winning the prize would be assessed.
In Kitchen v Royal Air Force Association , the client in an action against a negligent solicitor did not have to prove that he would have won the case, merely that he had lost “some right of value, some chose in action of reality and substance”.
In Allied Maple Goup Ltd v Simmons & simmons , the Court of Appeal held that in cases where a claimant’s loss depended on the hypothetical action of a third party, the claimant was entitled to succeed if he could show that there was a real or substantial, rather than a speculative, chance that the third party would have acted so as to confer a benefit on or avoid a risk to the claimant.
These cases had been distinguished to be decisions in contract law. The would give the potential odd result of different outcome between a doctor in private practice and an NHS doctor.
Moreover, examples could be found in tort law. In Spring v Guardian Assurance plc , Lord Lowry decided that, “…the plaintiff only has to show that by reason of that neglignece he has lost a reasonable chance of employment and has thereby sustained loss…He does not have to prove that, but for the negligence reference, [the third party] would have employed him.”
Other arguments trying to distinguish clinical negligence cases from economic loss cases included “lives should not be valued”, “viewing financial loss-type claims as loss of a chance of obtaining a benefit, rather than losing a chance of avoiding a detriment” , and that “human decision was predictable” . However, none could fully explain the difference.

Loss of chance in other countries
In Laferriere v Lawson , the Supreme Court of Canada denied the claim in loss chance where a doctor negligently failed to tell a patient that a breat lump biopsy was cancerous in 1971 and the cancer had spread when she was diagnosed in 1975.
In an Australian case Rufo v Hosking , it was sufficient for the claimant to prove on the balance of probability “that he or she had been deprived of a valuable chance”

2. The burden of proof

Another arena of the war to do justice was the reversal of the burden of proof in certain cases. Examples were the shooting cases decided in California and Canada where the claimant was shot by two defendants firing at the same time. Lord Wilberforce in Mc Ghee suggested the reverse of the burden of proof, “…it is a sound principle that where a person has, by breach of a duty of care, created a risk, and injury occurs within the area of that risk, the loss should be borne by him unless he shows that it had some other cause.”. This notion was quashed in Wilsher, Lord Bridge stated that this was a minority opinion which found no support in the other speeches in McGhee .

3. All or nothing approach v the porportional approach

The traditional principle was that “once liability is established, on the balance of probabilities, the loss which the plaintiff has sustained is payable in full. It is not discounted by reducing his claim by the extent to which he has failed to prove his case with 100 per cent certainty. …to do so [discounting] would be to propound a wholly new doctrine which had no support in principle or authority and would give rise to many complications in the search for mathematical or statistical exactitude.”
However, in Holtby v Brigham & Cowan Hull Ltd and Allen v British Rail Engineering Ltd , the Court of Appeal departed from the traditional binary approach and substituted this approach by the proportionate recovery principle, under which the defendant compensated the claimant for a fraction of his or her injury that represented the defendant's statistical share in that injury.
These decisions seemed in stark with Fairchild. One explaination was that the possibility of proportionate recovery was not raised before and, consequently, not adjudicated by the House of Lords. Apart from that, an important factual difference exists between the two settings. In both Holtby and Allen, it was practically certain that each defendant was positively established to have caused an unidentifiable fraction of that damage. In Fairchild, damage suffered by each of the claimants was causally attributable to only one defendant, who could not be identified. Yet, after Fairchild, claimants deserving recovery under the Holtby-Allen principle would no longer need to discharge the burden of proof upon which this entitlement depends. Instead of establishing each defendant's statistical share in his or her injury, any such claimant would only need to prove that he or she was wronged by each defendant, that the defendants' wrongs are indistinguishable, and that one of those wrongs necessarily brought about the injury.

4. Bolam test in causation

We have to mention Bolitho v City and Hackney H.A. , where the Bolam test was introduced into the area of causation where the defendant’s breach of duty consisted of an omission.

5. Res ipsa loquitur

To complete the list, the principle of res ipsa loquitur was sometimes, though rarely applied. Cassidy v Ministry of Health was the classic example.

6. Other principles in proofing causation

The problems with concurrent causes, consecutive causes and novus actus interveniens will not be discussed here.

Fairness

Objective of tort law
Among others, the main objective of tort law is to provide a remedy to those who have been harmed by others. The remedy would aim at putting the claimant to the original position before he was harmed. For the law to be fair, it would involve an ideal situation where the truth could be known, and the wrongdoer casuing the damage compensating the sufferer to an exact extend of the wrong.Of course this ideal could not be reached. There is a tension between distribution of risks (such as insurance schemes) and corrective justice.

Rights-based law v freedom based common law
There is another tension of a shift from freedom based common law towards rights-based law. The idea of human rights and patient rights is seeping into the courts. Doctors failing his duty of care tended to be considered liable: “the main point of this idea is normative: it relates to legal rights (norms), and not to causal issues (facts).…If a tortfeasor destroys or steals money which his victim is about to spend in a casino, he may not claim that he did not in fact cause any damage because the vicitm would have lost or spent the money anyway.”
Commented Charles Foster. “Where a duty exists for some reason that can be described in terms of human rights (and what duty cannot be?), a breach will entitled the claimant to damages on policy grounds, even if causation cannot be proved. The House of Lords has stretched the rules of causation before-notably in Fairchild. But Chester goes much further : it abolishes the requirement fo rcausation in any meaningful sense.”

Fairness to both parties
In Gregg, Lord Nicholls pointed it out clearly that “The present state of the law is crude to an extent bordering on arbitrariness. It means that a patient with a 60% chance of recovery reduced to a 40% prospect by medical negilgenc can obtain compensation. But he can obtain nothing if his prospects were reduced from 40% to nil. This is rough justice indeed.” And there would be “…a blanket release from liability for doctors and hospitals any time there was less than a 50% chance of survival, regardless of how flagrant the negilgence.”
However there were also uneasy feelings about the implications and unfairness for the defendants. Afterall, why should someone be paying for the damage which was not, by definition, caused by him?
Lord Phillips, “[In Fairchild] an employer who has contributed 20% of that exposure and thus 20% to the employee’s risk of contracting the disease will be liable in full to the employee.”
Lord Brooke commented on Fairchild, “If it was simply impossible for a claimant to prove negligence against anybody, then he could establish a 100% liability against everybody.”
And Baroness Hale, “If it is more likely than not that the defendant’s carelessness caused me to lose a leg, I do not want my damages reduced to the extent that it is less than 100% certain that it did so. On the other hand if it is more likely than not that the defendant’s carelessness did not cause me to lose the leg, then the defendant does not want to have to pay damages for the 20% or 30% chance that it did. A “more likely than not” approach to causation suits both sides.” “But why should the defendant not also be able to redefine the gist of the action if it suits him better?”

Development of the law

Letsay that the unfairness of the traditional principles in proofing causation were established. Should the law be developed to accommodate that?
Fairchild had established the principle that in exceptional circumstances, rules of causation could be modified on policy grounds. This was applied in Chester . However the Court of Appeal in Paul Davidson Taylor v White ruled that Chester did not establish a new general rule in causation and the relaxation could only be applied in exceptional cases.
In Gregg, the setting up of a new principle for the loss of a chance claim was also declined. “Adopting such a rule would involve abandoning a good deal of authority….There seem to me to be no new arguments or change of circumstances which could justify such a radical departure from precedent.”
Baroness Hales, “Well-settled principles may be developed or modified to meet new situations and new problems: the dicisions in Fairchild and Chester are good examples. But those two cases were dealing with particular problems which could be remedied without altering the principles applicable to the great majority of personal injury cases which give rise to no real injustice or practical problem.”
To add to the confussion, there was the case of Rees v Darlington Memorial Hospital NHS Trust , where the House of Lords purported to make a "conventional" but completely arbitrary award of £ 15,000 in recognition of a "legal wrong".
At Parliament v by the court
Another question was whether the development of law should be done by the Parliament or by the courts. The last time of review in this area was in 1978, the Pearson Report.
Lord Hoffmann, “But a wholesale adoption of possible rather than probable causation as the criterion of liability would be so radical a change in our law as to amount to a legislative act.”
Lord Phillips, “if special tests of caussation are developed piecemeal to deal with perceived injustices in particular factual situations, that the coherence of our common law will be destroyed.”
An analogy would be the principles developed by the courts in a piecemeal fashion for claiming of psychiatric damages.

Directions

Loss of chance approach revisited

Gregg had not put an end to all loss of chance claims. As Lord Phillips said, “Where medical treatment has resulted in an adverse outcome and negligence has increased the chance of that outcome, there may be a case for permitting a recovery of damages that is proportionate to the increase in the chance of that outcome.”

Strict liability

Another direction would be to impose strict liability for clinical negligence cases. However, claimant still have to prove that the damage would not have occurred in any event.

No fault compensation

Experience can be lent from New Zealand. However this might not solve the problem of causation since it will remain difficult to distinguish between a medical accident (which would be compensated) and the natural development of a disease or illness (which would not be compensated). Also it would need a strong cap to compensation .

Conclusion

There were unfair outcomes in the proof of causation in clinical negligence cases resulting from the strict application of the “but for” test in a balance of probability, all or nothing manner with the burden of proof resting on the claimant. The effect was most prominent in cases involving medical uncertainties in the causation of the damage, namely in cases with multiple causes and cases involving loss of chance. There had been cases advocating modification of the long-used legal principles. However these produced uncertainties, disturbed the coherence in law and also raised the concern of practicability; let alone the philosophical debate on causation and compensation. This is the right time for Parliament to review the whole process in a systematic and practical way.