1. Department of Preventive Medicine, Ajou University School of Medicine, Suwon, Korea.
2. Department of Policy Analysis and Management, College of Human Ecology, Cornell University, Ithaca, NY, USA.
3. Department of Preventive Medicine, Yonsei University College of Medicine, Seoul, Korea.
4. Institute of Health Service Research, Yonsei University, Seoul, Korea.
5. Department of Hospital Management, Graduate School of Public Health, Yonsei University, Seoul, Korea.
6. Department of Public Health Science, Graduate School, Korea University, Seoul, Korea.