His work has appeared in Journal of Marriage and Family, Nonprofit and Voluntary Sector Quarterly, Social Science Research, and Social Indicators Research, and he recently published America in the Philippines, 1899-1902: The First Torture Scandal (Palgrave-Macmillan, 2014). He wrote the report on informal volunteering for the 2011 United Nations State of the World’s Volunteering Report, which will be published as a chapter in the forthcoming Palgrave Handbook on Volunteering and Nonprofit Associations