He is titular Professor of Biostatistics in the University of Cambridge and Wellcome Trust and Juvenile Diabetes Research Foundation Principal Research Fellow in the Diabetes and Inflammation Laboratory, where he chairs the statistics group.
With Norman Breslow he has published important work on generalized linear mixed models.
Clayton read Natural Sciences at King's College, Cambridge and following this worked as a researcher in ergonomics and cybernetics.
He then worked as a statistician at the London School of Hygiene and Tropical Medicine, the University of Leicester and the MRC Biostatistics Unit in Cambridge before taking up his present position.
He was a lead statistician for the Wellcome Trust Case Control Consortium, a genome-wide association study.