Dr. Luigi Curini, Associate Professor of Political Science at the University of Milan, discusses how big data from social networks can be used to estimate public opinion about ISIS and terrorism. Dr. Curini shares his research using Twitter data to uncover how the Arabic community discusses the Islamic State on social media. He and his colleagues find that closing down Twitter accounts of ISIS supporters may lead to them becoming foreign fighters in Syria and Iraq, and that Islam is a major factor in generating both positive and negative sentiment about ISIS. We also discuss Dr. Curini’s upcoming book, Politics and Big Data: Nowcasting and Forecasting Elections with Social Media, which looks at how social media data can be used by researchers to more accurately predict election outcomes than traditional polling methods.