His main research interests are hepatocellular carcinoma, viral hepatitis, autoimmune hepatitis, fatty liver disease, and non-invasive markers of liver disease.
He has been Principal Investigator in over 165 sponsored and investigator-initiated clinical trials from phase I - IV. Professor Roberts has published more than 170 original articles across a range of high-impact journals including the New England Journal of Medicine, Lancet, Annals of Internal Medicine, Gastroenterology, Gut, Hepatology, and Journal of Hepatology.