The questions of whether preschool children benefi t more strongly when
early care and education (ECE) is at or above a threshold of quality,
has specifi c quality features, and/or is of longer duration were
examined in secondary data analyses of eight large ECE studies. These
issues are pivotal in recent ECE policies designed to improve school
readiness skills, especially for children from low-income families.
Threshold analyses examined whether quality had stronger associations
with gains in child outcomes in settings with high levels of quality
than those with lower quality. Features analyses considered whether
specific measures of instruction and of teacher-child interaction were
more predictive of gains than global quality measures. Dosage analyses
tested whether the amount of in ECE settings or in instruction in
specific content areas predicted child outcomes. Threshold analyses
provided some evidence for thresholds in measures of instructional
quality in relation to reading and language skills in meta-analyses
based on a prior-selected cut-points and, less clearly, in empirical
methods designed to identify cut-points. Analyses examining quality
features indicated stronger prediction of gains in child outcomes from
interaction-specific and content-specific measures than from global
measures. Propensity score analyses indicated that children had higher
school readiness skills at the end of preschool and in kindergarten if
they had two years of Head Start compared to one year. Finally, dosage
analyses indicated that children showed larger gains in content areas
when teachers spent more time providing instruction in those areas or
when children had fewer absences. No evidence of quality by quantity
interactions emerged. Implications of the thresholds findings for ECE
policies such as Quality Rating and Improvement Systems are discussed.
The dosage findings support the growing trend toward more than one year
of access to publicly funded preschool programs for low-income children
as well as increased focus on the content of ECE activities and
instruction to enhance language, literacy, and math skills.
