Using data from an urban public pre-k program, the authors add to and extend the emerging evidence base of the effects of public prekindergarten programs on child school readiness. They also use data collected in treatment classrooms to examine associations between teacher characteristics, fidelity-to-curricula, dosage and child outcomes. Their primary research questions are: (1) What is the causal impact of attending a prekindergarten program that implemented the "Building Blocks" mathematics curriculum at scale across an urban public school district on children's mathematics, language, literacy, executive function and emotional development?; (2) Within the treatment group, are teacher characteristics predictive of fidelity-to-curriculum and dosage?; and (3) Is higher "Building Blocks" fidelity-to-curricula and dosage associated with higher student outcomes, controlling for student- and teacher-level characteristics? Research took place in a large urban public school district in the Northeast. All prekindergarten programs were located in public elementary schools. The results add to the growing literature on the causal effects of large-scale state-funded prekindergarten programs. The authors find that a universal publicly funded prekindergarten program had positive impacts on child early numeracy, language, literacy, executive function, and emotional development. The authors' effect sizes are larger than those achieved in any RD prekindergarten study to date, which is particularly notable given that theirs is the only RD prekindergarten context in which there were uniform curricula in place. Due to the RD design of their study, they are unable to fit causal mediation models that would help them to definitively identify the causal mechanisms underlying their results. The path model they presented here using fidelity-to-curricula and dosage data on the treatment children in their treatment year found no significant associations between fidelity-to-curricula and dosage and child outcomes. Further analysis will allow them to better examine whether stronger effects in their study compared to previous prekindergarten RD studies thus could at least partially be a function of the chosen math and literacy curricula and the level of curriculum implementation in the district. (Contains 4 tables, 3 figures and 3 footnotes.)