Governments around the world have boosted their early childhood education and care (ECEC) engagement and investment on the basis of evidence from neurological studies and quantitative social science research. The role of qualitative research is less understood and under-valued. At the same time the hard evidence is only of limited use in helping public servants and governments design policies that work on the ground. The paper argues that some of the key challenges in ECEC today require a focus on implementation. For this a range of qualitative research is required, including knowledge of organisational and parent behaviour, and strategies for generating support for change. This is particularly true of policies and programs aimed at ethnic minority children. It concludes that there is a need for a more systematic approach to analysing and reporting ECEC implementation, along the lines of "implementation science" developed in the health area. (author abstract)