# Richard D. Gill

Richard David Gill (born 1951) is a British-Dutch mathematician. He has held academic positions in the Netherlands. As a probability theorist and statistician, Gill has researched counting processes. He is also known for his consulting and advocacy on behalf of alleged victims of statistical misrepresentation, including the reversal of the murder conviction of a Dutch nurse who had been jailed for six years.

## Education

Gill studied mathematics at the University of Cambridge (1970–1973), and subsequently followed the Diploma of Statistics course there (1973–1974). He obtained a Ph.D. in mathematics in 1979, with the thesis Censoring and Stochastic Integrals, which was supervised by Jacobus Oosterhoff and Carel Scheffer [nl] of the Vrije Universiteit, which awarded the doctorate.
During his career Gill has supervised 24 Ph.D. students including Sara van de Geer and Mark van der Laan.
Gill has said that he was "not much of an activist" as a student, but now feels guilty about not speaking up more at the time about perceived injustices, saying that this is partly because of an incident when working as a statistician in the 1970s when he helped on an experiment that severed the front legs of rats to investigate whether it would lead to the reshaping of their skulls. Gill said that this incident has stayed with him, as "what upset me most is that I didn’t have the strength of character to refuse to do that job".

## Career

In 1974 Gill was appointed at the Mathematical Centre (later renamed Centrum Wiskunde & Informatica, or CWI) of Amsterdam. After receiving his Ph.D., he continued to collaborate with Danish and Norwegian statisticians for ten years, co-authoring Statistical models based on counting processes, by Andersen, Borgan, Gill, and Keiding.
Gill became head of the Department of Mathematical Statistics at CWI in 1983. In 1988, Gill moved to the Department of Mathematics of Utrecht University, where he held the chair in mathematical stochastics. His PhD students include Sara van de Geer, and Mark van der Laan (co-advised by Peter Bickel). In 2006, Gill moved to the Department of Mathematics at Leiden University, where he held the chair of mathematical statistics. He retired from Leiden in 2017.
Gill became a citizen of the Netherlands in 1996.

## Advocacy

Gill has lobbied for retrials for nurses whose criminal convictions were based in part on statistical evidence, including Lucia de Berk and Benjamin Geen. Gill also said in a 2021 lecture that he suspects Beverley Allitt is innocent, and in a 2020 paper said the case "deserves fresh study".$^{:21:35}$ Gill states that his original involvement in campaigning for nurses stemmed from his wife encouraging him to get involved in the de Berk case, recounting her saying "They’re using statistics; you should get involved, do something useful".
De Berk was sentenced in the Netherlands to life imprisonment in 2003, after a legal psychologist gave testimony that there was great likelihood that de Berk committed a string of murders. Gill and other professional statisticians showed this statistical testimony to be fallacious. Continued scrutiny further invalidated the testimony by showing that the data had been collected to support the conviction of de Berk. After a campaign in which Gill helped, a retrial was ordered and de Berk was found not guilty; she received a public apology from the Dutch government, which also began negotiating financial compensation.
Gill's challenge of statistical evidence played a role in securing Daniela Poggiali's acquittal on murder charges in Italy in 2021.
Benjamin Geen's applications for a retrial have been rejected and in 2013 and 2015 Gill and other statisticians asked the Criminal Cases Review Commission (CCRC) to look into his case. The appeals were unsuccessful.
In 2022 Gill contributed to a peer reviewed report from the Royal Statistical Society on statistical issues in investigation of suspected medical misconduct.
Since the conviction of another nurse, Lucy Letby, on multiple charges of murder and attempted murder in 2023, Gill has expressed doubt over her guilt.

## Honours

Gill is a member of the Royal Netherlands Academy of Arts and Sciences. He is a past president of the Netherlands Society for Statistics and Operations Research. Gill was selected as the 2010–2011 Distinguished Lorentz Fellow by the Netherlands Institute for Advanced Study in Humanities and Social Sciences.

## Selected publications

* Andersen, Per K.; Borgan, Ornulf; Gill, Richard D.; Keiding, Niels (2012). Statistical Models Based on Counting Processes. Springer Science & Business Media. ISBN 978-1-4612-4348-9.
* Baddeley, Adrian J.; Gill, Richard D. (1997). "Kaplan-Meier estimators of distance distributions for spatial point processes". The Annals of Statistics. 25: 263–292. doi:10.1214/aos/1034276629.