Source: Teachers College Record, Volume 112 Number 3, 2010, p. 579-620.
There is much current interest in the impact of early childhood education programs on preschoolers and, in particular, on the magnitude of cognitive and affective gains.
Because this new segment of public education requires significant funding, 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.
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.
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.
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.
Consistent with the accrued research base on the effects of preschool education, significant effects were found in this study for children who attend a preschool program prior to entering kindergarten. Although the largest effect sizes were observed for cognitive outcomes, a preschool education was also found to impact children's social skills and school progress.
Specific aspects of the treatments that positively correlated with gains included teacher-directed instruction and small-group instruction, but provision of additional services tended to be associated with smaller gains.
Given the current state of research on the efficacy of early childhood interventions, there is both good and bad news.
The good news is that a host of original and synthetic studies have found positive effects for a range of outcomes, and this pattern is clearest for outcomes relating to cognitive development. Moreover, many promising variables for program design have been identified and linked to outcomes, though little more can be said of the link than that it is positive.
The bad news is that there is much less empirical information available for designing interventions at multiple levels with multiple components.