The surge in infant deaths at the hospital where Lucy Letby worked was not out of the ordinary, according to a mathematics professor.
Letby was found guilty of murdering seven infants and attempting to murder seven others at the Countess of Chester Hospital between 2015 and 2016.
The probe into their deaths was initiated after doctors observed an increase in “inexplicable” deaths on the neonatal unit, with nine deaths recorded in 2015 compared to the usual average of two. There was also a rise in the subsequent year.
However, John O’Quigley, honorary professor in the Department of Statistical Science at University College London (UCL), argued that it was a “serious statistical blunder” to compare these deaths to the national average.
He suggested that doctors should have compared the mortality rates at the worst-performing trusts, which would have demonstrated that the Countess of Chester was not an anomaly.
An analysis of the numbers reveals that Burton, Mid-Cheshire, Blackpool and Burton all experienced similar increases in the surrounding years.
O’Quigley wrote in The Telegraph: “There was in fact no evidence of anything extraordinary having taken place and that the belief in an inexplicable spike is based on an elementary, and very common statistical misconception. The inexplicable spike is in fact perfectly explicable.”
His conclusions are drawn from data provided by MBRRACEUK, an organisation dedicated to monitoring and investigating maternal deaths, stillbirths, and neonatal deaths.
Unlike other statistics, this data takes into account admissions, allowing for the calculation of each hospital’s death rate rather than just the overall number.
O’Quigley added: “The Countess of Chester [was] the poorest performer in 2015, but not so poor as to be seen apart from the others, that is to say an outlier, or in everyday language, a spike.”
Since Letby’s conviction, several scientists, statisticians, nurses, and doctors have questioned the evidence, expressing concerns that the trial did not sufficiently consider factors such as understaffing, poor practice, and cramped conditions in the baby unit.
A probe by the Royal College of Paediatrics and Child Health (RCPCH) has uncovered alarming deficiencies at a hospital ward between 2015 and 2016, highlighting both organisational failings and a critical shortage of staff.
The RCPCH investigation team unearthed grave concerns within the unit, identifying a troubling trend of “insufficient senior cover and a reluctance to seek advice” from higher-level consultants.
Experts cautioned that the presence of senior doctors was crucial, especially considering the delicate condition of the premature infants in their care, yet the staffing numbers often fell below safe recommended levels.
The report disclosed a worrying 21 percent deficit in nursing staff from 2014 to 2015, with temporary agency workers frequently called upon to fill the void.
Lady Justice Thirlwall is set to spearhead an inquiry into the hospital’s practices, which is scheduled to begin next month.