He is an expert in international relations and statistical modeling. In his research, he has studied how foreign publics view the United States and the foundations of the American world order; and why and when leaders decide to take their countries to war. He is currently involved in two major projects, one dealing with the domestic political foundations of U.S. hierarchy; the other dealing with the statistical modeling of policy ideas at the Central Bank of Japan, with Saori Katada and Gene Park.