Funded by Arnold Ventures and in collaboration with MDRC, the Expanding Children’s Early Learning (ExCEL) Quality study examined how curriculum combined with professional development helps teachers improve early childhood classroom quality and maximize improvements in children’s outcomes. In 53 centers across four localities, the research team used a random assignment design to compare classrooms implementing curriculum, paired with teacher training and in-classroom coaching, with a control condition that reflects the local context. MEF was involved in all phases of project implementation.