In Europe, and globally, substantial numbers of young people are at risk of social exclusion, and there is therefore a pressing need to develop more knowledge and innovation to create more inclusive and youth-friendly societies. Citizen social science might contribute to these needs, but the actual outcomes of citizen social science and its innovative potential is uncertain. <br/><br/>YOUCOUNT will therefore, through cocreative youth citizen social science (Y-CSS) including youths in the age of 15- 29 years as citizen scientists, produce new knowledge of positive drivers for social inclusion of youth at risk of exclusion, and cocreate innovations and policy-making. Moreover, to provide evidence of the actual outcomes of Y-CSS through hands on citizen science activities. <br/><br/>The project includes four substudies: 1) Development of a framework for Y-CSS together with a transdisciplinary consortium and multilevel platform of key experts and stakeholders in a European and international setting. 2) Implementation of a multiple case study of Y-CSS projects in nine countries across Europe where over 900 young citizen scientists and nine local living labs will cocreate innovations together. 3) Mixed-methods evaluation of the outcomes and impact of the Y-CSS activities, and a multi-criteria assessment of the costs and benefits of Y-CSS, and 4) Creation of social and scientific impact through widespread scaling up and continuity. These activities will lead to robust knowledge and scientifically reasoned measures to promote Y-CSS and social change. The project will support dissemination and education in Y- CSS, and make synergies with other CS related projects and initiatives, in particularly with citizen social science.