An impact and process evaluation of Early Years, a high-quality, two-year early childhood care and education program in Tallaght West, Ireland, that examines program effects on children's cognitive, language, and social development, on parental stress and the home learning environment, and on program quality, and that explores stakeholder perceptions of the program, based on data for children, parents, teachers, and classrooms from providers randomly assigned to deliver Early Years services, as well as on consultations with parents, teachers, and staff