The most recent analysis of a long-term NIH-funded study found that children who received higher quality child care before entering kindergarten had better vocabulary scores in the fifth grade than did children who received lower quality care.
The study authors also found that the more time children spent in center-based care before kindergarten, the more likely their sixth grade teachers were to report such problem behaviors as "gets in many fights", "disobedient at school," and "argues a lot."
However, the researchers cautioned that the increase in vocabulary and problem behaviors was small, and that parenting quality was a much more important predictor of child development than was type, quantity, or quality, of child care.
The study appears in the March/April 2007, issue of Child Development.
Jay Belsky, Ph.D., Director of the Institute for the Study of Children, Families and Social Issues and Professor of Psychology at Birkbeck University of London, was the first author of the current article.
The 1,364 children in the analysis had been tracked since birth as part of the NICHD Study of Early Child Care and Youth Development, the largest, longest running, and most comprehensive study of child care in the United States. Families were recruited through hospital visits to mothers shortly after the birth of a child in 1991 in 10 locations in the U.S. The children studied were not a representative sample of children in the U.S. population.
During the study, researchers measured the quality, quantity and type of child care the children received from birth until they were 54 months old. Child care was defined as care by anyone other than the child's mother that was regularly scheduled for at least 10 hours per week. This included care by fathers, grandparents and other relatives.
The researchers then evaluated the children's academic achievement, cognitive (intellectual) functioning from kindergarten through fifth grade and social development through sixth grade. Other factors, such as parenting quality and the quality of classroom instruction, were also measured. These other factors were taken into account when examining the association between early child care and children's subsequent development. The study tracked children's experience in child care. It was not designed to determine cause and effect and so could not demonstrate conclusively whether or not a given aspect of the child care experience had a particular effect.
For more information about the NICHD Study of Early Child Care and Youth Development, visit: http://www.nichd.nih.gov/research/supported/seccyd.cfm
In the current analysis, the researchers evaluated whether developmental characteristics that had been observed between kindergarten and 3rd grade were still present in fifth or sixth grade and if any new patterns had arisen.
An evaluation of the children in fifth grade showed that the children who had higher quality child care continued to show better vocabulary scores, a correlation that was seen previously from kindergarten to third grade. Vocabulary was assessed using the Picture Vocabulary subtest of the Woodcock-Johnson Psycho-Educational Battery Revised, which measures children's ability to name objects depicted in a series of pictures.
The researchers found that the correlation between high quality care and better vocabulary scores continued regardless of the amount of time the child had spent in child care or the type of care. The researchers wrote that this finding was consistent with other evidence indicating that children with greater early exposure to adult language were themselves more likely to score higher on measures of language development. However, child care quality was not associated with improved reading skills after 54 months of age.
The researchers also found that, as in the earlier grades, children with more experience in child care centers continued to show, through sixth grade, a greater frequency of what the researchers termed teacher-reported externalizing problem behavior. These behaviors were listed on The Child Behavior Checklist Teacher Report Form, which consisted of 100 problem behaviors.
Using this report form, teachers were asked to rate the child on items such as: child demands a lot of attention; argues a lot; bragging and boasting; cruelty, bullying or meanness to others; destroys things belonging to others; disobedient at school; gets into many fights; lying or cheating; screams a lot.
Children who had been in center care in early childhood were more likely to score higher on teacher reports of aggression and disobedience. This was true regardless of the quality of the center-based care they received.
The researchers emphasized that the children's behavior was within the normal range and were not considered clinically disordered.
It would not be possible to go into a classroom and with no additional information, pick out which children had been in center care, Dr. Belsky explained.
The study authors suggested that the correlation between center care and problem behaviors could be due to the fact that center-based child care providers often lack the training, as well as the time, to address behavior problems. For example, center-based child care providers may not be able to provide sufficient adult attention or guidance to address problems that may emerge when groups of young children are together, such as how to resolve conflicts over toys or activities.
Dr. James Griffin, the NICHD Science Officer for the Study, noted that the persistence of these findings demonstrates the importance of longitudinal research studies that follow children from infancy onwards.
"These findings add to the growing body of research showing that the quality and type of child care a child experiences early in life can have a lasting impact on their development" said Dr. Griffin.
The authors stressed the importance of continuing to follow the children's development in high school to see if the effects shown in the current paper persisted.