Many educational innovations show promise in small studies but never reach widespread classroom use. This study will examine co-design as a mechanism for transforming foundational research into usable interventions, and scaling and sustaining those interventions within diverse K-12 systems. Co-design is a collaborative process whereby teachers, researchers, and developers work together to design and test STEM innovations to improve teaching and learning outcomes. Drawing inspiration from medical research, where translation occurs from "bench to bedside" (Type I) and from bedside to widespread and sustainable practice (Type II), this project will study how co-design supports both the creation of usable tools and their successful integration into schools. Although co-design is increasingly used in federally funded education research, there has been no large-scale study of how it works in practice or contributes to the broader use and long-term sustainability of STEM innovations. Through a multi-method study of 100 NSF-funded STEM education projects, the team will examine outcomes of co-designed innovations, refine what is meant by co-design, identify the conditions that support and impede its success, and develop models of effective co-design. The project will advance the broader literature on theories and models of translation in education and in so doing help ensure that innovations actually reach and benefit all students. This study will examine co-design as a mechanism f