The NICHD started a longitudinal study in 1991 to study many aspects of child development. Similarly the NICHD study found that children who were in day care for more than 30 hours a week were 3 times more likely to show behaviour problems when they went to school.
By comparing the two studies we can see that the amount of time spent in day care plays an important role in whether or not children showed negative effects. However Violata and Russells meta-analysis showed that when time spent in day care exceeds 20 hours a week negative effects become apparent however the NICHD study found this time to be 30 hours therefore the results are contradictory and inconsistent.
The EPPE study was a large scale, longitudinal study of the progress and development of 3,000 children in various types of pre-school education across the UK. The results of the EPPE study found that high levels of day care, particularly nursery care in the first 2 years, may elevate the risk of developing anti-social behaviour.
To some degree the EPPE study supports the findings of Belsky and Rovines study as both found that the age of the child when placed in day care contributed to whether or not it was perceived to have negative implications. However the two studies can only be looked at comparatively to a certain extent as Belsky and Rovines study assessed infants under the age of 1 whereas the EPPE study assessed children up to the age of 7.
Clarke-Steward et al studied 150 children and found that those who were in day care were consistently more advanced in their social development than children who stayed home with mothers, enabling them to better deal with peer relationships. Likewise, the EPPE study found increased independence and sociability in the children who attended day care. Field (1991) found that the amount of time spent in full-time day care was positively correlated to the number of friends children has once they went to school.
However, although these findings suggest that full-time day care had positive effects on the child, the results clash with studies conducted by Belsky and Rovine. This may be due to individual differences of the children assessed in both studies, for example shy children may have appeared insecure when assessed using the strange situation technique by Belsky and Rovine. Moreover the positive correlation shown in Fields study cannot accurately be used as grounds to state that full-time day care causes children to be more popular as correlation is not causation.