Why his framework matters
Evidence-based medicine (EBM) is the formal discipline of evaluating clinical evidence on its methodological quality: study design, sample size, blinding, confounding, reproducibility, peer-review. It is the framework the NHS uses to decide whether a treatment works, whether a diagnostic test is reliable, and whether a clinical claim is supportable. It is also the framework that should apply to expert evidence in criminal trials where medical claims are the basis of conviction.
Prof. Heneghan’s public commentary on the Letby case applies the EBM framework to the trial evidence directly. His conclusion is that the Crown’s expert evidence does not meet EBM standards — the methodology, the sample size, the blinding, the confounding-control are each inadequate on current EBM criteria.
Professional background
- Professor of Evidence-Based Medicine, University of Oxford.
- Director of the Oxford Centre for Evidence-Based Medicine (CEBM).
- Practising GP.
- Sustained public-engagement work on evidence-based policy across Covid-19 response, NHS screening, diagnostic-test reliability, and contested medical claims.
- BMJ, Spectator and broadsheet contributor on evidence-based policy.
The EBM framework applied to Letby
- Study design. The Crown’s expert evidence was retrospective, hypothesis-first, unblinded case review. Under EBM, this is observational and carries specific bias risks.
- Confounding control. The cluster’s confounding factors — outbreak, staffing, infrastructure, acuity mismatch — were not formally controlled in the Crown’s expert analysis.
- Reproducibility. A different expert panel applying modern EBM methodology (the Shoo Lee Panel) reaches the opposite conclusion on the same casebook. This is the form reproducibility takes in clinical-evidence evaluation: when independent methodologically-sound replication produces opposite results, the original result is not reproducible.
- Peer-review. The Crown’s expert opinions were not published in peer-reviewed form. The Panel’s framework and the Joint Insulin Report have peer-review-layer support. The peer-reviewed literature layer is against the Crown’s framing.
Why this is load-bearing
EBM is not a fringe framework. It is the canonical UK methodology for evaluating clinical evidence. The Oxford CEBM is its flagship institution. When the director of that institution publicly states that the Crown’s evidence does not meet EBM standards, that is a specific institutional judgment about the reliability of the evidence base the conviction rests on.
The CEBM framework applied to the Letby case
Prof. Heneghan is Director of the Centre for Evidence-Based Medicine (CEBM) at the University of Oxford. The CEBM framework formalises what evidence-based medicine requires from a medical claim: clearly-defined hypothesis, control group or comparator, methodology specified before data collection, peer-reviewed validation, and explicit acknowledgement of uncertainty. His public-commentary application of the CEBM framework to the Letby trial evidence identifies four specific EBM failures: retrospective pattern-matching without pre-registration, absence of control, hypothesis-first reasoning, and non-peer-reviewed methodology. The institutional UK EBM community’s judgment is that the Crown’s methodology does not meet EBM standards.
Prof. Heneghan’s framework is the formal academic-EBM counterpart to Dr Ben Goldacre’s Bad Science framework. The two frameworks operate at different levels of formality (academic-EBM vs popular-audience EBM) and reach the same conclusion on the Letby case methodology. The institutional coherence of the Oxford EBM voice is one of the load-bearing features of the post-conviction critique.
The Oxford CEBM institutional position
The CEBM is one of the leading global centres for evidence-based medicine research and is institutionally well-positioned to take public positions on UK clinical-evidence questions. Prof. Heneghan’s appointment as Director carries CEBM’s institutional standing into his public-commentary engagement with the Letby case. His sign-on to the post-conviction methodological critique is therefore not the position of a single researcher taking a personal view; it is institutionally backed by Oxford’s standing in evidence-based medicine.
Why this voice matters for the conviction-safety question
The Cannings principle (2003) established that where serious disagreement exists between reputable experts on medical-causation evidence, prosecutions should not proceed. The CEBM framework is one of the formal frameworks against which ‘serious disagreement between reputable experts’ can be assessed. Prof. Heneghan’s sustained engagement with the Letby evidence establishes that serious EBM-framework disagreement exists on the Crown’s methodology — which is one of the data points the CCRC review will weigh under the ‘real possibility’ test.