The Childcare Development Block Grant (CCDBG) Implementation Research and Evaluation Planning Grant offers the Massachusetts Department of Early Education and Care (EEC) opportunities to better understand how aspects of the current subsidy system shape the stability of children's participation in high quality early education and care, and to identify and evaluate cost-effective ways to improve stability. Through a review of ongoing research and exploratory analysis of existing data as well as interviews with families, EEC will identify subgroups of families and children who demonstrate greater instability in access to subsidized early education and care, and will work to understand the drivers of instability and inequitable access to high quality early education. The grant will then support the planning of an evaluation of potential policy changes to increase equitable access, which could be funded through Phase II, if offered.