Anderson, L.M., Shinn, C., Fullilove, M.T., Scrimshaw, S.C., Fielding, J.E., Normand, J., CarandeKulis, V.G. (2003)

Early childhood development is influenced by characteristics of the child, the family, and the broader social environment. Physical health, cognition, language, and social and emotional development underpin school readiness. Publicly funded, centre-based, comprehensive early childhood development programs are a community resource that promotes the wellbeing of young children. Programs such as Head Start are designed to close the gap in readiness to learn between poor children and their more economically advantaged peers. Systematic reviews of the scientific literature demonstrate effectiveness of these programs in preventing developmental delay, as assessed by reductions in retention in grade and placement in special education.

Camilli, G., Vargas, S., Ryan, S., & Barnett, W. S. (2008)

Background/Context: There is much current interest in the impact of early childhood education programs on pre-schoolers and, in particular, on the magnitude of cognitive and affective gains.

Purpose/Objective/Research Question/Focus of Study: Because this new segment of public education may require substantial resources, accurate descriptions are required of the potential benefits and costs of implementing specific preschool programs. To address this issue comprehensively, a meta-analysis was conducted for the purpose of synthesizing the outcomes of comparative studies in this area.

Population/Participants/Subjects: A total of 123 comparative studies of early childhood interventions were analyzed. Each study provided a number of contrasts, where a contrast is defined as the comparison of an intervention group of children with an alternative intervention or no intervention group.

Intervention/Program/Practice: A prevalent pedagogical approach in these studies was direct instruction, but inquiry-based pedagogical approaches also occurred in some interventions. No assumption was made that nominally similar interventions were equivalent.

Research Design: The meta-analytic database included both quasi-experimental and randomized studies. A coding strategy was developed to record information for computing study effects, study design, sample characteristics, and program characteristics.

Chambers, B., Cheung, A., Slavin, R., Smith, D., & Laurenzano, M. (2010)

This report systematically reviews research on the outcomes of programmes that teach young children in a group setting before they begin reception. Study inclusion criteria included the use of randomised or matched control groups, and study duration of at least 12 weeks. Studies included valid measures of language, literacy, phonological awareness, mathematical, and/or cognitive outcomes that were independent of the experimental treatments. A total of 40 studies, evaluating 29 different programmes met these criteria for outcomes assessed at the end of preschool and/or reception/ kindergarten. The review concludes that on academic outcomes at the end of preschool and/or reception, six early childhood programmes showed strong evidence of effectiveness and five had moderate evidence of effectiveness. Of the 29 programmes reviewed, eight are available for implementation in the UK. A few longitudinal studies have followed their subjects into secondary school, and even adulthood. These studies show that comprehensive programmes, from a cognitive developmental perspective rather than a solely academic focus, had better long-term effects on social adjustment outcomes such as reductions in delinquency, welfare dependency, and teenage pregnancy, and increases in educational and employment levels.

Gilliam, W. & Zigler, E.F. (2000)

The number of state-funded preschool programs for low-income children has increased dramatically over the past few decades, and recent research has indicated that these programs vary considerably along a variety of dimensions. By 1998 only 13 of the current 33 state preschool programs (which serve children 3 to 5, provide some form of classroom-based educational service, and are primarily funded and administered at the state level) had completed a formal evaluation of the program’s impact on child outcomes. This paper presents a critical meta-analytic review of these evaluations, providing measures of standardized effects for all significant impacts to facilitate comparisons across differing domains of outcome and evaluative methods. Although several methodological flaws in these studies are identified, the pattern of overall findings may offer modest support for positive impacts in improving children’s developmental competence in a variety of domains, improving later school attendance and performance, and reducing subsequent grade retention. Significant impacts were mostly limited to kindergarten and first grade; however, some impacts were sustained several years beyond preschool. The results of these studies were similar to evaluations of other large-scale preschool programs for lowincome children, such as Head Start. Modest outcome goals are warranted for preschool programs serving low-income children, for example, the promotion of school readiness. Suggestions are presented for improved preschool and early intervention program evaluation.

Gorey, K.M. (2001)

Some scholars who emphasize the heritability of intelligence have suggested that compensatory preschool programs, designed to ameliorate the plight of socioeconomically or otherwise environmentally impoverished children, are wasteful. They have hypothesized that cognitive abilities result primarily from genetic causes and that such environmental manipulations are ineffective. Alternatively, based on the theory that intelligence and related complex human behaviors are probably always determined by myriad complex interactions of genes and environments, the present meta-analytic study is based on the assumption that such behaviors can be both highly heritable and highly malleable. Integrating results across 35 preschool experiments and quasi-experiments, the primary findings were: (a) preschool effects on standardized measures of intelligence and academic achievement were statistically significant, positive and large; (b) cognitive effects of relatively intense educational interventions were significant and very large, even after 5 to 10 years, and 7 to 8 of every 10 preschool children did better than the average child in a control or comparison group; and (c) cumulative incidences of an array of personal and social problems were statistically significantly and substantially lower over a 10- to 25- year period for those who had attended preschool (e.g., school drop-out, welfare dependence, unemployment, poverty, criminal behavior). The need for a very large, well-controlled, national experiment to either confirm or refute these provocative, review-generated findings is discussed.