This factsheet from ARACY reviewed research and practice evidence in prevention and early intervention to identify factors that promote positive child development and how more effective systems can be built to provide better life outcomes for children with a specific focus on why we need to implement better family service systems. The paper provides key insights for policy and practice, including: (1) Current systems are failing children. There is a need for programs with better population-level impacts on child health. (2) Holistic approaches are necessary for solving the problems. (3 ) There needs to be common goals and a common language to focus on the outcomes that matter. (4) Evidence must be central to how the system works. Evidence needs to be collected, understood, valued, shared and actioned. (5) We should think nationally but act locally, with shared goals and values and local solutions. (6) We should leverage universal services and promote child development, identify needs early and target services to those who need it before crisis occurs. (7) Implementation is critical and must use the science of how we make proven ideas work in practice, at scale.