Dr. Ellenberg's work focuses on the design and analysis of clinical trials and observational studies and, in particular, on selection bias and generalization, the etiology of childhood neurological illnesses and conditions, prematurity, AIDS and cardiovascular disease. He is an elected fellow of the American Statistical Association, the Society for Clinical Trials and the AAAS, and is an elected member of the International Statistical Institute. He served as president of the American Statistical Association in 1999 and of the International Biometric Society in 1988.