Brian K Chen1, Y Tony Yang2, Chun-Yuh Yang3. 1. Department of Health Services Policy and Management, Arnold School of Public Health, University of South Carolina, 915 Greene Street Suite 354, Columbia, SC 29208, USA. 2. College of Health and Human Services, George Mason University, 4400 University Dr, Fairfax, VA 22030-4444, USA. 3. Department of Public Health, College of Health Sciences, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan.