SI, Supplemental Instruction and Collaborative Learning, is a model for learning developed in the US to reduce dropouts and improve university grades. It is based on a model student (SI leader) who plans and conducts weekly lessons (SI meetings). This project involves the development and scale-up of a concrete, system changing and scalable tool to increase knowledge development in primary school and reduce social exclusion. This is done by a completely new implementation of the SI model, where teachers, and not Didici consultants, are turned into protagonists. The project will be carried out in Skåne based on one primary school in Burlöv and two in Malmö (Rosengård and Husie) and in a new educational context at SFI in Malmö.