Regional and national identities are significant determinants of people’s support for secession. Most previous works, however, have implicitly assumed that the relationship between identity and support for secession is linear and not affected by the context in which individuals interact. This methods case, based on a paper published in Political Geography, explains why and how we challenged this assumption. In short, we examined whether (and in what direction) the context plays a role in explaining the relationship between identity and support for secession. Our research design was empirical and had two stages. First, we employed a pool of more than 22,500 individuals interviewed in Catalonia in different surveys carried out between June 2011 and November 2014. Second, we used data from a survey including 1,500 individuals interviewed in Barcelona, the capital of Catalonia. In this methods case, we guide you through the most important steps of the project, namely, the relevance of our research question, the research design, and the challenges and problems we encountered.