1. From the RAND Corporation, Pittsburgh, PA (TD), Santa Monica, CA (CEB, JJE, and RBD), and Washington, DC (NL); the Centers for Disease Control and Prevention/National Center for Health Statistics, Hyattsville, MD (MH); San Diego State University, San Diego, CA (BKF); the State University of New York Stony Brook, Stony Brook, NY (LH); and the University of California Los Angeles/RAND Corporation,