Researchers in multilevel modeling (MLM) report on new statistical advances, methodological issues, and applications in MLM, and examine problems that occur when trying to use MLM in applied research in areas such as power, experimental design, and model violations. The book will be of interest to researchers in advanced statistical training and experience in applying MLMs, especially in the areas of education, clinical intervention, psychology, and other behavioral sciences. The book can also be used as a supplement for an introductory graduate course. Reise teaches measurement at the University of California-Los Angeles. Duan teaches psychiatry and biostatistics at the University of California-Los Angeles.