Dr. Localio's current methodological work centers on computing risk difference and relative risk estimates in complex designs such as occur in multicenter studies and meta-analyses, as well as on issues of confounding by center. His inital first-authored articles have appeared in Statistics in Medicine, American Journal of Epidemiology, Journal of Clinical Epidemiology, New England Journal of Medicine, the Journal of the Americn Medical Assocition (JAMA) and Annals of Internal Medicine. 

His ongoing collaborative work includes studies on the effectiveness of mammography, accuracy and reliability of multimodality radiological imaging for breast cancer, utilization and outcome of antibiotic use among children across hospitals, and effectiveness of computerized reminders for immunizations for children. He currently collaborates with investigators in general internal medicine, gastroenterology, pediatrics, cardiology, pulmonary medicine and infectious diseases (child and adult). He has served as an associate editor of Annals of Internal Medicine since 1997. His current teaching responsibilities include a full semester class (EP 521) on Statistical Methods in Epidemiological Research, which he has taught for eight years. He regularly provides formal mentoring for students in the MSCE program.

Dr. Localio joined the faculty of the CCEB in 1997. Prior to arriving at Penn, he was recognized as an authority on the methodological issues of research in the identification of medical adverse events and in medical professional liability; he has been the principal investigator of both an RO1 and an RO3 grant on this subject.