This factsheet from ARACY reviewed research and practice evidence in prevention and early intervention to identify factors that promote positive child development and howmore effective systems can be developed to provide better life outcomes for children with a specific focus on identifying effective programs and services. The paper provides key insights for policy and practice, including: (1)There is good evidence on what works for many strategies, programs and services, and decision-making should use this evidence. (2) Databases already exist to identify good investments to make to target different issues. (3) The evidence needs to be easier to find, to understand, to use and to scale up. (4) There is a need to build better evidence and learn about how best to implement the programs that are effective. (5) We need more Australian data, particularly on the costs and benefits of what works here.