L. Khoury, Uncertain Causation in Medical Liability, D.Phil. Thesis, University of Oxford, 2003 (excerpts)

L. Khoury, Uncertain Causation in Medical Liability, D.Phil. Thesis, University of Oxford, 2003 (excerpts).

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  Probabilities lie at the heart of the assessment of causation. Nothing is certain in this world and one can often assess only the probability of existence of facts and events.
  
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  Damages are in theory not calculated in proportion to the judge’s conviction that the def. caused the damage, i.e. on the basis of its causative probability. This fiction is reflected in what is called in CoL the all-or-nothing rule.
  
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  The all-or-nothing rule has been criticized as leading in every case to an unfair result by either under-deterring or over-deterring defendants. There came a system of proportional recovery – if it is established that there is a 40% probability that the def.’s negligence was the cause of the plt.’s damage, the plt. may recover compensation for 40% of this damage. This amount reflects the risk created by the def. and the damage suffered by the plt. through that risk, or, in other words, the proportion of the chance of avoiding the damage that the def. deprived the plt. of.
  
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  Loss of chance is the best known expression of the principle of proportional recovery. This theory argues that if, before the def.’s fault intervened, a plt. possessed a chance to make a gain or to avoid a loss, and the fault destroyed that chance, the plt. can obtain compensation for the value of the lost chance instead of claiming for the negative situation in which he has been left.
  
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  This concept has the clear advantage of allowing the plt. to recover at least part of his damage despite the uncertainties surrounding causation, while holding the def. liable only for a portion of the loss, based upon the extent of his causal responsibility for it.
  
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  The loss of chance concept has been originally applied in cases now called classic and subsequently been extended to medical cases.
  
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  There is little doctrinal and judicial resistance to the acceptability of loss of chance reasoning in the so called classic loss of chance cases, even though this head of damage is by definition hypothetical.
  
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  In these cases, often argued in ks, the def.’s negligent action or omission crystallizes the plt.’ situation, and the plt. is thereby altogether prevented from taking the chance. Consequently, the hoped-for-end-result remains forever hypothetical. E.g. a lawyer has allowed the limitation period of his client’s claim to lapse; a person has failed to buy a lottery ticket for a friend after agreeing to do so…
  

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  In all of these cases, the language of chance allows one to assess the plt.’s hypothetical damage by calculating not the value of the end resultend-result expected but that of the plt.’s chance of achieving that end resultend-result, gain the advantage, or avoid the loss.
  

-The chance is calculated on the basis of the probability of realization of the expected result and consequently the plt. receives compensation for only a portion of his injury.

-The chance must be capable of being assessed objectively, independently of the value of the hoped-for benefit.

-The lost chance must be causally related to the def.’ fault.

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  The doctrine’s extension to cases involving medical faults in which the causal link b/w the final damages – death, sickness or disability – and the doctor’s fault is uncertain is more controversial and has provoked a very active debate in all of the jurisdictions studied.
  
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  In the context of medical liability, the concept is most useful when, even though causation b/w the doctor’s fault and the plt.’s damage is not established on the basis of the traditional standards, it allows the plt. to plead that before the medical act was undertaken, he had a chance of cure or of survival which the def.’s fault destroyed.
  
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  Hence, losing a chance of recovery is considered a form of legal damage in its own right, independent of the final outcome suffered by the patient.
  
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  Thus, the plt. is not required to make the impossible demonstration of the exact cause of the final damage (X). He has to prove only that the physician’s fault caused a distinct damage, the loss of chance (Y).
  
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  Only the French judiciary currently agrees to compensate patients for their loss of chance of survival or recovery. The Quebec and Canadian case law has strictly rejected the application of the doctrine to medical negligence cases.
  
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  Quebec courts generally assess causation in medical liability instances without recourse to the loss of chance analysis, preferring to focus on the actual damage which has occurred. While the intermediate damage represented by the loss of chance may be mentioned in the course of analysis, the courts’ preference is to satisfy themselves not only that chance was lost but that on the balance of probabilities that chance would have been realized.
  
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  E.g. in Lawson, the SCC not only rejected the argument that loss of chance constitutes a redefinition of the damage, but also believed that, used in the medical context, the idea artificially bypasses the causation requirement.
  
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  This position did not, however, constitute a revolution; it had already been largely adopted by the doctrine and most of the case law on the subject.
  
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  Argument in favour the doctrine of loss of chance
  
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  Avoid the unfairness of the traditional all-or-nothing approach;
  
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  It is a valid type of damage independent of the actual future damage, i.e. the benefit missed or the injury that was not avoided.  the loss of chance solely seeks the calculation of the loss.
  
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  Loss of chance accounts better for the fact that statistical chances do not necessarily reflect the plt.’s personal chance.
  
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  In lighting the plt.’s burden of proof, loss of chance helps him deal with the imbalance of knowledge and financial resources b/w him and the def. doctor.
  
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  Ensure the quality of professional practice
  
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  Argument against the doctrine  the distinction b/w the classical and medical loss of chance
  
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  Taking of the chance: whether or not the plt. had the possibility of taking the chance.
  

  Classic cases	Medical cases
  The chance is destroyed and the hoped forhoped-for result will never be obtained and therefore remains contingent.	The medical fault decreases the plt.’s chances of recovery; but the plt. is not prevented from taking his chance.
  Loss of chance analysis allows the courts to assess the damage despite the fact that it has not yet been made real.	The chance is exhausted and the result is no longer hypothetical. The plt. suffers an identifiable and known damage and the loss of the chance is only a step leading to his final damage, which must occur in order for the compensation question to become relevant.
  	The final damage is a past accomplished event, the cause of which is uncertainty.

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  Consequently, the concept of loss of chance has no role to play where the chance has been taken and the final outcome fulfilled.
  
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  Type of uncertainty:
  

  Classic cases	Medical cases
  When the taking of the chance has been halted and the resulting damage remains contingent, the question to be decided is one of damage the depends on future hypothetical events (‘What would have happened if … ’).	When the chance has been taken and the outcome is realized, the court’s task is to retrace the historical facts which led to the plt.’ loss (‘What did happen’).
  The question can be answered only by assessing the chance of a favourable outcome.	The question must be answered on the balance of probabilities.

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  this distinction is difficult to apply b/w it is possible to reformulate every case as one of uncertainty about either past facts or hypothetical future events.
  
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  General Implications of Loss of Chance
  
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  Loss of chance may denature the traditional requirements of causation and evidence and even lead to a complete revolution in the rules of civil liability in two ways:
  
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  It provides a conceptual justification for by-passing the fundamental requirement of showing causation;
  
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  It theoretically allows recourse to proportional liability in every case.