Evidence-based reform is transforming education at all levels, both in providing effective models for use in schools and in linking policy to effective practice on a broad scale. As early education moves from a concern with effects of preschool versus no preschool to focus on creating and evaluating effective preschool models capable of improving language and literacy outcomes and of being broadly replicated, evidence should play a leading role. This article describes promising areas for development and evaluation, particularly for improving the language and literacy of children from economically challenged communities. (author abstract)