Dr. Neff Walker is a Senior Scientist in the Department of International Health at JHSPH. As a member of IIP, his research and teaching focus on the evaluation of large-scale RMNCH programs and modeling the impact of RMNCH interventions. He is the Principal Investigator for RADAR and the Lives Saved Tool (LiST). Before coming to JHSPH he spent four years at UNICEF as the Senior Advisor for estimation and modeling of the impact of HIV/AIDS as well as serving as UNICEF's focal point for the Child Health Epidemiology Reference Group (CHERG). From 1998 through 2003, Neff worked as the Senior Advisor for statistics and modeling at the United Nations Program on HIV/AIDS. In both positions, a primary focus of his work was the development and implementation of standard methods for estimation and modeling related to disease burden. He earned his PhD in Cognitive Psychology from Columbia University. He is from the US.