William Dow's research analyzes economic aspects of health insurance, health behaviors, and health and demographic outcomes. In addition to his United States research he has also conducted international health research in areas such as Western Europe, Mexico, Costa Rica, China, and sub-Saharan Africa. One recent strand of research investigates the role of health policy in shaping mortality trends and patterns, with several papers focusing on the particular role of health insurance in the United States, Costa Rica, Taiwan, and elsewhere. He is also Co-PI of the new Costa Rican Healthy Aging Survey (CRELES), a longitudinal effort to study how it is that Costa Rica has achieved life expectancy greater even than that of the United States. The first wave of this nationally representative survey was collected 2004-2006, including extensive biomarkers such as those comprising allostatic load measures, with longitudinal follow-ups now being conducted.