NURSERY schools and classes offer higher-quality learning than reception classes, say researchers.
Professor Kathy Sylva, of Oxford University, said: "We found reception classes were not as good for children under the age of five as nursery classes, although they were quite good on literacy.
"Reception classes may have 28 children to one teacher. Nurseries will have a ratio of one teacher to 13 children. Reception classrooms were smaller ... (children) have less space for play activities and less outdoor space."
She was due to present her findings at a symposium on the effective provision of pre-school education at the BERA conference.
Professor Sylva is taking part in a huge study - the largest of its kind in Europe - monitoring the relative effectiveness of different forms of early education and care.
She and her colleagues, Professor Edward Melhuish, Professor Pam Sammons, Professor Iram Siraj-Blatchford and Brenda Taggart, are following the progress of 3,000 children between the ages of three and seven in different pre-school environments.