and outcomes in community programs with different features. This research provides information about the effects of typical variations in program quality on the general population of children (including, but not limited to, economically disadvantaged children).
Studies of programs for English-language learners. This relatively small literature is similar to the first two, but it focuses specifically on the effects of variation in the approach to second-language acquisition on competence both in the primary language and in English.
Descriptions of exemplary international programs. This literature suggests features that contribute to program quality, but provides relatively little empirical verification.
Studies of clinical and program interventions for children with disabilities and the relationship of salient child and family characteristics to intervention methods. This research confirms the value of educational, therapeutic, and social services for infants and young children with disabilities.
Beginning in the early 1960s, preschool programs were developed to provide educational experiences to young children growing up in poverty. These programs sought to improve learning and development for these children in response to growing awareness of social inequalities and changing beliefs about the role of the environment in development. The context for these new efforts was vividly described by Caldwell and Richmond (1968:341):
During the late 1950’s and early 1960’s a sure path to ostracism in the field of early childhood education was to emphasize attendance at nursery school as an influence on intellectual development. Debunking the Iowa studies [conducted at the Iowa Child Welfare Research Station of the State University of Iowa by Skeels, Wellman, and colleagues], which demonstrated intellectual gains associated with nursery school attendance, became a popular sport…and the implication that such an experience could have lasting cognitive effects was subject to ridicule.