Why her case matters for the Letby review
Prof. Richard Gill — the Leiden statistician now publicly involved in the Letby case — led the statistical critique that exonerated Lucia de Berk. His reading of the Letby evidence is calibrated to having walked through precisely this pattern of error once before. His 2024 “tale of two Lucies” lecture makes the structural parallel explicit.
The facts of her case
- Paediatric nurse at the Juliana Children’s Hospital in The Hague.
- In 2001 the hospital noticed that a cluster of patient deaths and medical emergencies had occurred during her shifts. An internal review identified her as the common factor.
- Prosecuted on the basis of that shift coincidence plus post-hoc medical re- interpretation of the deaths as suspicious.
- Convicted in 2003 of four murders and three attempted murders. Further convictions on appeal in 2004. Sentenced to life.
- Statistical centrepiece: a calculation that the probability of Lucia being on shift for so many incidents by chance was on the order of 1 in 342 million.
- Medical centrepiece: re-interpretation of previously-explained deaths as unexplained, and unexplained deaths as poisonings.
How her case was overturned
Prof. Richard Gill led the statistical critique from 2006 onwards. The three structural points:
- Selection effect. The incidents selected for the statistical calculation were those that looked suspicious in retrospect; suspicion was partly formed by noticing Lucia’s presence. The calculation was therefore retrospective, not predictive.
- Unblinded reinterpretation. Deaths that had been clinically routine at the time were re-read as suspicious after the pattern was noticed. The re-reading was not blinded.
- Specialist framing. The case was presented by medical witnesses who were not statisticians. No qualified statistician gave evidence for the prosecution.
The Dutch Supreme Court reopened the case in 2008 on the basis of Prof. Gill’s submissions, and Lucia was acquitted in April 2010 — after seven years in prison.
The structural parallel to Letby
The procedural parallel is uncomfortably close:
- Cluster noticed at one hospital.
- Common factor: a nurse who worked more unsociable shifts than average.
- Retrospective, unblinded medical re-interpretation.
- Statistical chart presented without a qualified statistician.
- Medical expert not currently in routine practice in the relevant sub-specialism.
- Hospital management with institutional interest in a “bad apple” explanation.
For the full treatment, see our Lucia de Berk parallel analysis.
Why this biography is on the site
Prof. Richard Gill’s published work on the Letby case is part of a continuous line of reasoning running from the de Berk exoneration. Readers unfamiliar with the Dutch case cannot fully weigh his critiques of the Letby statistics. This biography supplies the reference. Lucia’s case also supplies a specific counter-example to the institutional argument that “the courts have decided, so the matter is settled”: the Dutch courts had decided in 2003, had confirmed on appeal in 2004, and were still wrong. Correction took until 2010.