Sarah E. Boslaugh, Ph.D., M.P.H., has over 20 years of experience in statistical analysis, grant writing, and teaching; her employers and clients have included the New York City Public Schools, Montefiore Medical Center, Kennesaw State University, Washington University School of Medicine, andSaint Louis University. She served as editor-in-chief for the "Encyclopedia" "of Epidemiology "(SAGE, 2007), and has published three additional books: "An Intermediate Guide to SPSS" "Programming: Using Syntax for Data Management "(SAGE, 2004), "Secondary Data Sources for Public Health: A" "Practical Guide...