I am Geballe Professor in Stanford’s School of Humanities and Sciences; a Professor in the Department of Political Science; and a Senior Fellow in the Freeman-Spogli Institute, affiliated with CISAC and CDDRL.

My research has focused mainly on political violence, civil and interstate war in particular.

Worse than War: The Global Costs of Violence (co-authored with Anke Hoeffler) was published by Princeton University Press in May 2026. This book estimates the prevalence and costs of both collective and interpersonal violence.

I have also written off and on about international relations theory; democracy and democratization; ethnic conflict; foreign aid and institution building; and post-conflict reconstruction.

I am a member of the National Academy of Sciences, the American Academy of Arts and Sciences, and the Council on Foreign Relations.