Main contribution
Led the statistical critique that overturned Lucia de Berk's conviction. Public author of the statistical critique of the Letby shift-rota chart since 2023.
May 2026: Thirlwall Inquiry report delayed to at least September 2026 · six-baby inquests relisted to 2027 · CCRC review active · Shoo Lee Panel: no medical evidence of deliberate harm.
Conflict-map · Post-conviction statistical experts
Mathematical statistics; Lucia de Berk lead
Led the statistical critique that overturned Lucia de Berk's conviction. Public author of the statistical critique of the Letby shift-rota chart since 2023.
The shift-rota chart is a textbook example of selection bias (the Texas sharpshooter fallacy).
Cross-reference on the main experts conflict-map page.
This page is the conflict-map view (role in the Letby case + position on disputed evidence). For the full biographical reference — background, career, publications and public commentary — read the dedicated biography.
Post-conviction statistical experts.
Bayesian networks in legal evidence
Main contribution: Sustained Bayesian-network analysis of the Letby evidence. The most detailed publicly available Bayesian critique.
Key claim: Posterior probability of guilt on the trial evidence does not meet the criminal-law threshold.
Related evidence
Medical statistics (Warwick)
Main contribution: Operational analysis of the Letby shift-rota chart identifying four specific methodological failures.
Key claim: The chart conflates rate and count, uses the wrong denominator, has no null-hypothesis comparison, and pattern-matches against pre-selected events.
Related evidence
Statistics (Cambridge); past-president RSS
Main contribution: UK's most widely recognised statistical-communicator voice. Framework for statistical evidence in criminal trials applied directly to the Letby chart.
Key claim: Statistical-evidence standards established after Sally Clark apply to the Letby chart and were not met.
Related evidence