After such events, traumatic stress and other psychological sequelae can have substantial impact on children’s health and wellbeing. A growing number of studies track child symptoms and recovery after an acute trauma exposure. And there is a growing body of research evaluating the effectiveness of interventions to prevent or treat the consequences of a wide range of types of trauma. But small samples often limit generalizability, and wide variation in measures makes cross-study comparisons challenging. The Child Trauma Data Archives project is an international collaborative effort to address this challenge.