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Statistics: Lucy Letby – Serial Killer or Coincidence? Hypothesis Testing & The Legal System – Professor Jane Hutton, University of Warwick
23rd September 2025 @ 13:30 - 14:15
What hypothesis test would you use to test whether the death rate on a medical unit has suddenly increased? How would you follow up a significant result which showed the risk of death had doubled?
The conviction of a UK nurse, Lucy Letby, for murdering seven newborn infants has resulted in debate about whether the conviction was safe. Investigating clusters of deaths, infectious diseases or collapses in healthcare settings pose various statistical challenges for forensic investigations.
In this interactive session, we will explore the standard statistical techniques and role of hypothesis testing in epidemiology and public heath. However, their use is not established within criminal investigations. We will consider how statistics are used in actual convictions and miscarriages of justice. Discussion of the important implications of this for Lucy Letby and similar cases will be encouraged.
Lecturer Profile: Professor Jane Hutton is a University of Warwick professor who works in interdisciplinary statistics. She was engaged by the Cheshire police to assist with collecting and evaluation evidence related to deaths at the Countess of Chester Hospital and Lucy Letby. She has collaborated with health professionals and lawyers for many years. Her more mathematical research is inspired by questions raised by patients, doctors and lawyers.
Our events are designed so that a group of students can take part from a classroom or students and teachers can take part as individuals, either from school or from home. There is no charge to take part.
As a live, participative event, this session will not be recorded but slides and other resources will be shared after the event, where available.
Suitable for: Aged 16+ pre-university students studying, or with a possible interest in studying, Statistics, Law and related disciplines. Student groups as well as students and teachers joining individually are very welcome.
Preparation/Pre-Reading: Students may wish to consider the topic in advance and questions they have. Students can also think about questions about studying at university level.
The IT Setup: The event will be run on Zoom and participants will be able to join using laptops, tablets, and mobile devices. If you are joining as a school group, we recommend connecting with one device and projecting on to a whiteboard. You will be able to interact with the speaker via typed comments and questions and/or via a microphone. Full details will be sent to those who have registered (see below) prior to the event.
Booking a Place: This is free for schools and colleges. If you would like to take part in this event, please register your interest using the link to the registration form below: