Students have numerous opportunities to learn outside the classroom. However, with great choice comes great variability of both quality and of intent. To evaluate the effectiveness of out-of-school programs generally—as well as individual programs specifically—we must know their intended effects (program goals) as well as their actual effects (program outcomes). Despite numerous existing evaluations and even more numerous claims, many programs and evaluations lack strong empirical support, suffer from biases, and are ripe for perverse incentives. In this paper, we propose greater adoption of large-scale collaborative research to provide more precise and accurate information about: effects of participation; heterogeneity of effects across contexts or demographic groups; resolve disagreements; and evolve to exploring new questions with greater confidence in previous findings. Implementing large-scale collaborative research practices that have helped catalyze a credibility revolution in psychology will help stakeholders make more informed decisions.