Janet is Emeritus Professor Medical Statistics in the School of Population Health and Environmental Sciences. Her main research interests are in the use and extensions of statistical methods in epidemiological studies, and the communication of biostatistics to non-statisticians. Her clinical research includes paediatric studies, particularly preterm birth, cancer and other long-term conditions. Her main methodological interest is in making outcomes clinically meaningful and accessible to non-statisticians.

She has written three biostatistics books for non-statistical researchers including the new 2nd edition of 'Oxford Handbook of Medical Statistics' and 'Presenting Medical Statistics'. She is a former NIHR Senior Investigator and took up the post of Professor of Epidemiology and Biomedical Data Science at Dartmouth Geisel School of Medicine, USA in 2020.