When the Literature Isn't Enough

Clinical negligence and personal injury litigation often requires experts to navigate competing research, evolving science and differing schools of clinical thought.

The recent High Court decision in Abbott & Others v Ministry of Defence [2026] is a useful reminder that courts are interested in more than published literature alone. Ultimately, expert evidence must be grounded in sound clinical reasoning and applied to the individual before the Court.

The claim was brought by more than 3,500 former armed forces personnel who alleged they had suffered Military Noise Induced Hearing Loss (MNIHL) as a result of noise exposure during their service.

A central issue was how military hearing loss should be diagnosed. The claimants argued that the traditional Coles, Lutman and Buffin (CLB) guidance, widely used in hearing loss litigation, was not well suited to military cases. Instead, they relied upon a newer methodology known as M-NIHL, developed to identify hearing loss caused by military impulse noise such as gunfire, artillery and explosions.

The claimants also argued that noise induced hearing loss may continue to worsen long after exposure to damaging noise has ceased. The Ministry of Defence disputed both propositions, maintaining that the established clinical understanding remained the more reliable approach.

After hearing extensive expert evidence, Mr Justice Garnham concluded that the newer M-NIHL methodology was generally preferable in military hearing loss cases. However, the court rejected the suggestion that noise induced hearing loss continues to progress indefinitely after exposure has ended, finding the scientific evidence insufficient to support such a conclusion.

Perhaps most importantly for expert witnesses, the judgment emphasised that no diagnostic methodology should replace careful clinical assessment and professional judgement.

Lessons for Clinicians and Experts

First: Diagnostic tools should support, not replace, clinical judgement.
Although the court preferred the M-NIHL approach in this particular context, it was clear that no methodology is appropriate in every case. Experts should be prepared to explain why a particular diagnostic framework has been used and how it applies to the facts before them. A report that relies solely on a formula or guideline without demonstrating independent clinical reasoning is unlikely to be persuasive.

Second: Be ready to justify your methodology.
A significant proportion of the judgment was devoted to analysing the strengths and weaknesses of competing diagnostic approaches. The court carefully examined the evidence underpinning each methodology before reaching its conclusions. For experts, this reinforces the importance of understanding not only how a methodology works, but also its limitations, assumptions and areas of uncertainty.

Finally: Emerging science must be distinguished from established evidence.
The court accepted that some developing theories regarding progressive hearing deterioration were scientifically plausible. However, plausibility alone was not enough. The available evidence did not justify departing from the accepted clinical position. Experts relying on emerging research should therefore be careful to distinguish between developing hypotheses and conclusions that have achieved broader scientific acceptance.

For experts preparing medico-legal reports, Abbott is a useful reminder that courts are rarely persuaded by literature alone. Published research, guidelines and diagnostic tools remain important, but they are aids to expert reasoning rather than substitutes for it. The most persuasive evidence continues to come from experts who can explain not only what they think, but how they reached that conclusion and why it is supported by both the science and the facts of the case.