Children in low-quality childcare lag behind those in high-quality care in language development, according to new research.

Surprisingly, the same holds true even when family educational and economic backgrounds are similar.

Researchers from the FPG Child Development Institute and the UNC School of Education examined how the quality of childcare impacts language development in young children. They collected data from three childcare programs and evaluated each on the number of children per class, teachers' education levels and the child-to-caregiver ratio. The lowest quality site had large classes, less teacher education and a significantly higher child-to-caregiver ratio — one caregiver per eight children as compared to one to two and one to three in the higher quality programs.

"Language is a critical aspect of school readiness and pre-literacy skills," said lead author Lynne Vernon-Feagans, professor of Child and Family Studies at UNC. "Research shows that early vocabulary and language skills are related to later standardized reading test scores."

In every measurement used, children in higher-quality childcare did better on language tests than those receiving the lowest quality care. And childcare quality made an even greater difference over time. This was especially true for vocabulary; children in higher-quality care used twice as many words by age 3 as those in the lowest quality care.

All of the children came from dual-earner families with similar economic and educational advantages.

"These results suggest that policymakers and educators should promote smaller teacher/child ratios and teacher classes in child development to promote better language interactions between young children and their caregivers," Vernon-Feagans said. "Parental income and education were not factors in this research. It was the quality of care that was related to children's language development."

The study appears in the March 2007 issue of the Journal of Applied Developmental Psychology.