The effects of high-quality child care for toddlers can last well into children's teenage years. Researchers from the National Institutes of Health in the U.S. studied 1,364 children who were followed from the age of 1 month to 15 years as part of the NICHD Study of Early Child Care and Youth Development (SECCYD), the largest, longest running and most comprehensive study of child care in the United States. The researchers reported the type, quantity and quality of child care the children received during their first 4 1/2 years with high quality child care being characterised by the caregivers' warmth, support and cognitive stimulation of the children they were looking after. Even at the age of 15 the children who had been in higher-quality child care as a toddler scored slightly higher on measures of academic and cognitive achievement and were slightly less likely to behave badly. However, the teenagers who had spent the most hours in child care in their first 4 1/2 years were slightly more likely to behave impulsively and take risks at 15 than those who had spent less time in child care.