The Dimensions of Success observation tool (DoS), defines twelve indicators of STEM program quality throughout 4 broad domains: 1) Features of the Learning Environment, 2) Activity Engagement, 3) STEM Knowledge and Practices, and 4) Youth Development in STEM. While primarily developed for after-school, it can be used to observe activites led by teachers, private sector scientists, after-school workers, and more. The dimensions can be used to describe goals for young people’s experiences through cross-sector collaboration. The DoS tool allows researchers, practitioners, funders, and other stakeholders to track the quality of STEM learning opportunities and to pinpoint strengths and weaknesses. DoS was developed with support from the National Science Foundation (NSF) by the Program in Education, Afterschool and Resiliency (PEAR), along with partners at Educational Testing Services (ETS) and Project Liftoff.