His research is directed towards achieving rational behavior in intelligent systems, based on the principles of probability theory, decision theory, Bayesian learning and game theory. He received his Ph.D. in 2000 from Stanford University, where his dissertation on probabilistic reasoning received the Arthur Samuel Thesis award. feffer has published technical papers on probabilistic reasoning, strategic reasoning, agent modeling, temporal reasoning, and database systems. He was awarded the NSF Career award in 2001 for work on strategic reasoning, and the Alfred P. Sloan Foundation Research fellowship in 2002.