A new study that looked at more than 75,000 children in day care in Norway found little evidence that the amount of time a child spends in child care leads to an increase in behavioral problems, according to researchers from the United States and Norway.
Several prior studies in the U.S. made connections between the time a child spends in day care and behavioral problems, but the results from Norway contradict those earlier findings, the researchers report in the online version of the journal Child Development.
"In Norway, we do not find that children who spend a significant amount of time in child care have more behavior problems than other children," Boston College Associate Professor of Education Eric Dearing, a co-author of the report, said. "This runs counter to several US studies that have shown a correlation between time in child care and behavior problems."
Dearing, who conducted the study with researchers from Norway and Harvard Medical School, said the Scandinavian country's approach to child care might explain why so few behavioral problems were found among children included in the study group.
In Norway, parental leave policies ensure that most children do not enter child care until the age of one. In addition, unlike the U.S., Norway maintains national standards and regulations for child care providers, which may lead to higher quality care, said Dearing.
"Norway takes a very different approach to child care than we do in the United States and that may play a role in our findings," said Dearing, an expert in child development, who co-authored the study with Dr. Claudio O. Toppelberg, a psychiatrist and researcher with Harvard Medical School and its Judge Baker Children's Center, and Norwegian researchers Henrik D. Zachrisson and Ratib Lekhal.
With a large sample size capable of revealing even the narrowest of connections between early care and behavior, the team went through a number of statistical tests to examine methods used in earlier U.S. studies and to scrutinize their own findings.
When the researchers examined the sample using methods identical to those most commonly used in U.S. studies, they produced a similar link between child care hours and behavior. But the researchers took issue with the common approach, which is to compare children from different families who spend varying amounts of time in child care because of family choices. Although earlier U.S. studies using this method tried to control for parent and family characteristics – such as income and education, mental health and intelligence – the method leaves open the possibility that differences between families in areas other than child care choices are, in fact, the true causes of behavior problems.
Given the scope the Norwegian data, the researchers were able to compare children who came from the same families but who spent varying hours in child care, effectively resolving the issue of external influences. When they did this, they found no statistical evidence to point to increased behavioral problems. Siblings who spent more time in day care exhibited the same behavior as siblings who spent less time in day care, Dearing said.
The researchers went even further, probing the sample in an effort to reveal even the most minor, yet statistically significant, links between hours spent in child care and behavioral problems.
"The biggest surprise was that we found so little evidence of a relation between child care hours and behavior once we introduced conservative controls in an effort to ensure that any association was in fact causal," said Dearing. "With such a very large sample, even very, very small correlations would be statistically significant. But we found no association in our most sophisticated models."
Dearing and colleagues report that important next steps will be follow-up studies involving Norwegian children into later childhood and adolescence, times through which child care effects persist in the US, and collecting more data from countries outside the US to determine the child and family policy environments in which child care does or does not appear to put children at risk.