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Legal Mind Case and Commentary No 11: Material Contribution: Little or Large? - Dr Hugh Koch & Dr Chrissie Robertson, Hugh Koch Associates

19/11/16. Case: Williams v The Bermuda Hospitals Board (2016). In a recent paper by Hardwicke (2016), a Judicial Committee of the Privy Council judgement was described which is potentially highly persuasive. The original case involved a man Mr. W who complained of abdominal pain. Following a delay in investigating his appendix ruptured and he developed complications.

In the first hearing, it was held that Williams had failed to prove that these complications were, on balance of probabilities, caused by the hospital’s failure to diagnose and treat him expediently. While a small award for pain and suffering during the period of avoidable delay was made, nothing was awarded in relation to any injury caused by the complications. Williams had failed on the ‘but for’ test. On appeal the decision was overturned. The Court of Appeal of Bermuda found that the delay had materially contributed to the complications. The Court considered that the trial judge had erred in his consideration of causation, setting the threshold too high. Causation was not an ‘all or nothing’ matter. The proper test should not be whether the negligent delay had caused the injury (i.e. not the traditional ‘but for’ test), but rather whether the breaches of duty by the hospital had contributed materially to the injury. The Privy Council upheld the Court of Appeal’s decision.


This raised issues of whether either material contribution can only apply to cases where there are simultaneous contributing causes not successive, or can it be sufficient to have a cumulative cause of an injury, caused in part by the negligence of the hospital. In this case, it was found that, on the balance of probabilities, the negligent delay ‘materially contributed to the process, and therefore materially contributed to the injury to the heart’.

This has, according to Hardwicke, widened the concept of material contribution. Causation is central to every legal case (Young, 2015). The index event may be ‘material’ or ‘contributory’ to an injury, and must be seen in the multifactorial array of the available evidence. The expert needs to analyse this from a biopsychosocial perspective taking into account pre-existing, precipitating and perpetuating factors, plus also taking into consideration personal and social resilience and protective factors. He must also apply logicality and, where possible mathematic apportionment to the expression of a robust opinion which cogently reflects a theory of causation which is as scientific and reliable as possible.

At a legal level, according to Young (2013) the ‘but for’ test of causality stance constitutes a high bar context. An index event in a personal injury case can contribute materially and substantially to a resultant liable psychological injury although not uniquely or even majorly so (Young, 2015).

It is our view that the medical/clinical and legal fields need to consider Young’s concept of ‘biopsychosocial’ causality in order to specific its multifactorial components and interaction (Young, 2015). Judicial and medico-legal decision making in relation to multifactorial attribution needs further debate.

In a previous Legal Mind Commentary (No. 2, Koch and Addy, 2016), it was suggested that, in reality, a comprehensive definition of the term ‘material contribution’ remains elusive. The terms ‘minimal’ or ‘moderate’ contribution are ill defined and do not reliably withstand scrutiny, and ‘scientific proof’ is hard, if not impossible, to find in some cases.

This case has widened the concept of material contribution in applying not only to simultaneous causes but also to sequential or cumulative ones. In clinical practice, where injuries are sustained and there are multiple causal factors, it is often the case that these factors operate cumulatively in bringing about the outcome. It is perhaps rarer to see multiple causes operating simultaneously and although in the legal context applying material contribution only to such situations aids clarity, examination of cumulative causal factors in personal injury cases is perhaps more representative of how things work in practice.

Material contribution is difficult to define however – how substantial does a contributing factor have to be to be classed as materially contributing to an injury? And if cumulative effects are to be considered, can we place limits on the time elapsed between a liable factor occurring and other, non-liable factors occurring which together cumulatively resulted in the injury?

The Williams case has raised important issues in the application of material contribution to personal injury cases and generated discussion and debate in this complex area and is welcomed.


Dr Hugh Koch and Dr Chrissie Robertson
Hugh Koch Associates, Cheltenham, Gloucestershire, UK.


Hardwicke RR (2016) Material Contribution and Williams PIBULJ 09/07/16.

Koch HCH and Newns K (2016) Causation of Psychological Injuries and Index Incident Assessment. Exp. Wit. J. Summer, 26-30

Koch HCH (2016) Legal Mind: Contemporary Issues in Psychological Injury and Law. Expert Witness Publications

Koch HCH and Addy K (2016) Material Contribution and the ‘but for’ test. Legal Mind Case and Commentary No. 2. PIBULJ. 14/04/16.

Williams V. The Bermuda Hospitals (2016) UKPC 4

Young G (2015) Causality in Criminal Forensic and in Civil Disability Cases: Legal and Psychological Comparison. Int J Law Psychiatry. 42-43, 114-120.

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