Elizabeth A. Stuart, PhD, is an assistant professor in the Department of Mental Health and the Department of Biostatistics at Johns Hopkins Bloomberg School of Public Health. She received her PhD in statistics in 2004 from Harvard University, working under the direction of Donald Rubin. Dr. Stuart has extensive experience in methods for estimating causal effects, particularly as applied to mental health, prevention, and education. Her publications include applied and theoretical papers on the use of matching methods such as propensity scores and she has written software for implementing matching methods in R. She also has extensive experience with designing and analyzing randomized experiments, multilevel modeling, and bayesian methodology. Prior to her time at Hopkins she was a researcher at Mathematica Policy Research, Inc. and she has served as a consultant on propensity score methods for the RAND Corporation, Genzyme, Inc., the Urban Institute, and the American Institutes of Research. She also has extensive teaching experience, including semester-long and one-day short courses on the estimation of causal effects.