Stephen J. Kunitz and Robert Lillis are with the Department of Community and Preventive Medicine, University of Rochester School of Medicine, Rochester, NY. W. Gill Woodall, Denise R. Wheeler, and Everett Rogers are with the Center on Alcoholism, Substance Abuse, and Addictions, The University of New Mexico, Albuquerque. Hongwei Zhao is with the Department of Biostatistics, University of Rochester School of Medicine.