Abstract: This study tests an intervention that introduces a structured curriculum for five-year-olds into the universal preschool context of Norway, where the business as usual is an unstructured curriculum. We conduct a field experiment with 691 five-year-olds in 71 preschools and measure treatment impacts on children’s development in mathematics, language, and executive functioning. The nine-month intervention has effects on child development at post-intervention and the effects persist one year following the end of the treatment. The effects are mainly driven by the preschools identified as low-quality at baseline, indicating that a structured curriculum can reduce inequality in early childhood learning environments
