‘Causation, Statistics and Survivability’
Case Commentary: R (Chidlow) v Senior Coroner for Blackpool and Flyde  EWHC 581 (Admin) 12 March 2019
This case raised two interesting issues for the Divisional Court: (1) the distinction between identification of the cause of death and survivability and (2) whether causation can be proved by statistical evidence relating to survivability.
On the evening of 27 July 2009, a neighbour heard banging and screaming inside 38-year old Carl Bibby’s home in the Kirkby area of Liverpool. She called the police who arrived at the scene shortly before midnight. The Police repeatedly called for an ambulance to attend. At the inquest, the ambulance service, NWAS, acknowledged that a failure to upgrade the case in response to a second Police call had been error. This failure meant that the case was not prioritised with a ‘red’ (8-minute) response time and that the ambulance arrived 26 minutes later. In the course of the delay Mr Bibby suffered a cardiac arrest and died.
Notwithstanding the evidence on causation from five pathologists the precise cause of Mr Bibby’s death was unclear. A consultant in Critical Care & Emergency Medicine gave evidence that the chances of survival if treated by paramedics before Mr Bibby was in cardiac arrest would have been “markedly increased … irrespective of the underlying diagnosis.” He repeated that it was more likely than not that Mr Bibby would have survived with early treatment but conceded that “you never quite know” what the outcome would have been for any individual patient. The consultant based his opinion on his clinical experience, evidence of Mr Bibby’s condition, his review of the medical evidence in the case and the absence of any underlying disease or infection and a number of statistical studies.
The Coroner ruled that “it cannot be established, in my judgment, that the rendering of care would have prevented the death if we do not know what the cause of death was” and in the absence of knowing the cause of death it was not safe (on the Galbraith plus test) to leave the issue of causal link between delay and Mr Bibby’s death to the jury. In other words, where the cause of death is unknown questions of survivability will be inherently speculative and therefore unsafe.
The Divisional Court held that the Coroner had erred in his approach and that the absence of clear evidence as to causation did not prevent the jury from being able to consider the possible effect of the delay in treatment where there is sufficient evidence upon which such a delay had more than minimally, negligibly to trivially contributed to death (as per Tainton).
The case also raised the thorny issue of whether causation can be proved by statistical evidence. Pepperall J identified the following principles from the authorities:
“52.1 In deciding whether to leave an issue of causation to a jury, a coroner should consider both limbs of the Galbraith Plus test. Causation should be left where there is evidence upon which the jury could properly and safely find that, on the balance of probabilities, the event or omission had more than minimally, negligibly or trivially contributed to death. That is the crucial test.
52.2 In considering whether it is safe to leave such an issue to the jury, a coroner must have regard to all relevant evidence. In addition to evidence relating to the particular deceased and the circumstances of his or her death, that may include general statistical evidence drawn from population data such as the rate of survival in a particular group.
52.3 Such general statistical evidence alone is, however, unlikely to be sufficient. For example, even where the rate is over 50%, a raw survival rate for the group into which (without the relevant event or omission) the deceased is said to fall is unlikely to be sufficient because, without evidence supporting the proposition derived from the population data , a jury could not safely conclude that he or she would have fallen into the category of survivors. As Croom-Johnson LJ put it, being a figure in a statistic does not of itself prove causation.
52.4 In most cases, there will be other evidence as to whether the deceased probably would or would not have fallen in the group of survivors. Where there is apparently credible additional evidence of causation which, if accepted, together with the general statistical evidence could properly lead the jury to find on the balance of probabilities that the event or omission more than minimally, negligibly or trivially contributed to death then it will usually be proper and safe to leave causation to the jury”.
In this case the Consultant’s expert opinion was founded on a number of considerations: the Consultant’s own experience, his review of the available medical evidence, the absence of evidence of any underlying health conditions, accounts of Mr Bibby’s condition at the time he fell ill as well as statistics on survival data drawn from a number of studies. Of course the jury would not have been bound by the Consultant’s opinion but the issue of survivability should have been a matter left to them.
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