This project is a synthesis study to investigate the effectiveness of informal STEM and ICT programs to maximize impact and broaden participation of youth participants in STEM pathways. We focus on two research questions: (1) How and to what extent do informal, out-of-school time (OST) STEM and ICT learning experiences impact K-12 participants’ awareness, interest, and engagement in STEM majors and STEM careers? (2) What aspects of programs were most effective in maximizing impact and broadening participation of underrepresented groups?