I am interested in studying social, group and political behaviour. I apply techniques from mathematical modelling and data science to these topics. My work detects clusters of people on Twitter, revealing groups who share a sense of identity. I characterise those groups according to their language use and can track their growth and spread in the network. I have developed methods to target particular groups of interest on Twitter and then sample members of those groups. This can have great value for mapping social/political groups, understanding their dynamics, and tracking their evolution.