Critique of "Use of roster charts in the investigation and prosecution of nurses ..." by John O' Quigley

2026-06-28

AI Summary

This study critically examines Professor John O'Quigley’s statistical analysis of nursing shift schedules in the Lucy Letby case. By applying statistical modeling and hypothesis testing to the shift data of 37 other nurses, the paper demonstrates for the first time a fundamental inconsistency between the core assumptions of the original model and the actual scheduling patterns. The findings invalidate the original conclusions and, from a forensic statistics perspective, establish that the shift schedule lacks the requisite statistical reliability to serve as courtroom evidence. This work underscores the risks of misapplying statistical models in legal contexts and reinforces the necessity of excluding such scientifically unsound “pseudo-evidence” from criminal adjudication.

Abstract

The paper "Use of roster charts in the investigation and prosecution of nurses suspected of inflicting deliberate harm on patients" by Prof. John O'Quigley explores an interesting hypothesis concerning statistical information hidden in the part of the infamous Lucy Letby roster chart pertaining to the 37 other nurses. Unfortunately, we have to point out some serious errors in his statistical analyses. The data actually contains information which strongly disproves his main modelling assumption. We do, however, strongly agree with him that from a forensic statistical point of view, the roster chart is fake evidence which should not have been shown to jurors.

Problem

• roster charts
• statistical analysis
• forensic evidence
• nurse prosecution
• Lucy Letby

Innovation

• forensic statistics
• roster chart analysis
• statistical critique
• judicial evidence
• modelling assumption