His research examines how political opinions form and change as a result of discussion, deliberation and argument in domains such as legislatures, campaigns, the judiciary, and social media, using techniques from machine learning, automated text analysis, and social network analysis. Recent projects using social media explore deliberative quality in online political forums, and predict elections using Twitter textual data (paper forthcoming in the AJPS). Current projects include visualizing the rhetorical structures of political speeches, experimental designs for optimizing political advertisements, and the prediction of judicial opinions and ideologies.