In two project phases, INSIDE provides comprehensive and reliable information for the first time on the current implementation of school inclusion at lower secondary level and on the transition of pupils with special educational needs to upper secondary level, the vocational training system or another life situation. INSIDE creates a sound data basis by surveying various groups of people involved in inclusion, such as children and young people with and without special educational needs, parents, teachers, school management and school support staff. On the one hand, this can contribute to the creation of a basis for political objectives to promote inclusion in everyday school life and at the transition to education and work, and on the other hand it is made available to the scientific community for further research purposes.