Child Care Choices is an example of new early childhood research based on a relationship between policy makers and researchers. It is also an example of large-scale longitudinal team-based research into early childhood in Australia. The ongoing study addresses the professional problem for practitioners and policy makers of the increasing use of multiple care settings and changes to care arrangements in the early years and their possible impacts on child development. The project will follow an initial sample of 693 families with a child aged from birth to three years over a three-year period. An ecological framework is used to include the influences on child development of characteristics of the children and their families, their city or country location, as well as their childcare history and current care arrangements. Development is measured in terms of children’s health, motor development, social and emotional development, language and communication as well as emerging literacy and numeracy. The article discusses the unique features of the project in Australian early childhood research, its history, preliminary findings, and the potential of this kind of large-scale, longitudinal team-based research conducted in partnership with policy makers to contribute to policy as well as to theoretical debate.