Atsushi Miyawaki1, Yusuke Tsugawa2,3,4. 1. Department of Public Health, Graduate School of Medicine, University of Tokyo, Tokyo, Japan. 2. Division of General Internal Medicine and Health Services Research, UCLA David Geffen School of Medicine, Los Angeles, CA, USA. ytsugawa@mednet.ucla.edu. 3. Department of Health Policy and Management, UCLA Fielding School of Public Health, Los Angeles, CA, USA. ytsugawa@mednet.ucla.edu. 4. UCLA Center for Health Policy Research, Los Angeles, CA, USA. ytsugawa@mednet.ucla.edu.