Adult/child ratio and group size in early childhood education or care to promote the development of children aged 0–5 years: A systematic review

Worldwide, a large number of infants, toddlers, and preschoolers are enroled in formal non-parental early childhood education or care (ECEC). Theoretically, lower adult/child ratios (fewer children per adult) and smaller group sizes are hypothesised to be associated with positive child outcomes in ECEC. A lower adult/child ratio and a smaller group size may increase both the extent and quality of adult/child interactions during the day.