Can a claimant in a clinical negligence claim who is unable to prove the precise mechanism by which a positive outcome would have been achieved still succeed on causation? Yes, held the Court of Appeal in Schembri v Marshall. The judgment also provides a useful summary of authorities dealing with the use of statistics for causation purposes in clinical negligence cases.
On 25 April 2014 Mrs Marshall visited her GP Mr Schembri complaining of chest pains. She was not referred to hospital and she died the next morning as a result of an untreated pulmonary embolism. Mr Marshall, the Deceased’s husband, brought a claim for damages against Mr Schembri alleging that the Deceased should have been referred to hospital where she would have received life-saving treatment and the failure to do so caused her death. Mr Schembri admitted a breach of duty but denied causation, arguing that the deceased would likely have died even if she had been so referred.
At first instance Stewart J considered extensive expert evidence and medical literature concerning survival rates following a pulmonary embolism. The Judge found the Claimant was unable to prove that the Deceased would have been in the 64-75% who would have survived a cardiogenic shock (paragraph 115). The Claimant was further unable to prove a specific train or mechanism which, absent the admitted negligence, would have saved the Deceased.
However, Stewart J then considered a separate, overriding question: was it nevertheless more likely than not that the Deceased would have survived had she been referred to hospital? Stewart J decided that this was all the Claimant needed to prove and it was unnecessary to establish the precise mechanism by which survival would have been achieved. In considering the wealth of statistical evidence as a whole Stewart J found that the Deceased’s chances of survival would have significantly increased had she been in hospital when she became unstable but made no findings as to exactly why this was the case. The claim succeeded.
The Defendant appealed arguing inter alia that:
The Court of Appeal reviewed the following authorities when coming to a decision:
Having considered the above, the Court of Appeal upheld the ‘common sense and pragmatic’ decision of Stewart J (paragraph 53). Having found that the specific mechanism could not be proved the Judge took a ‘legitimate pause for thought’ and looked at all the statistical data available. This was necessary because of the large number of unknowns and because the actual outcome was unknown due to the appellant’s negligence (paragraph 51). Further, whilst it clearly suited the Appellant to rely on statistical evidence when considering whether a specific chain of events was established he could not ‘sweep away such evidence’ when it became inconvenient in respect of a more general question (paragraph 52).
The Court of Appeal nonetheless emphasised that statistics were not determinative of causation and each case remains fact specific (paragraph 56). This was not a case in which statistics were used to transpose a strong case in the appellant’s favour into a decision in favour of the respondent. Instead Stewart J considered the Deceased’s individual condition and her likely presentation at hospital and legitimately considered statistical evidence when coming to his conclusion. Defendants should not therefore be too perturbed by the decision; causation arguments may still be advanced even where the Claimant has obtained favourable statistical evidence, particularly where the facts and circumstances suggest the case outlies the statistical norm.
  EWCA Civ 358
  EWCA Civ 1719
  EWCA Civ 25
  2 AC 176