Paolo Santini is a PhD student in labor economics at the Paris School of Economics under the supervision of Jérôme Bourdieu and Thomas Breda. He is also part of the “Labor Chaire”, from which he is financed. He holds a master degree from the University of Bologna and a second one from the Paris School of Economics. His main research interest is to understand the reasons behind the formation (or dismantling) of groups, and what factors might be important in this process. Currently, his works are focused on trade unions and their internal organizational structure both in France and the US.