It found that 'on the whole' the maintained sector offered the highest quality provision for children aged up to three-and-a-half.
The study set out to examine the quality of care for children aged three-and-a-half because less is known about provision for very young children.
Observations took place in infant and toddler rooms in 103 settings between February 2004 and July 2005. Quality varied widely, with 70 per cent of rooms observed rated adequate, 23 per cent good and 7 per cent 'less than minimal' quality.
The report said, 'The private sector had the lowest mean quality rating, but also displayed the broadest variation in quality, with some centres operating at a very high standard.'
Maintained status was 'a strong predictor of provision quality', the report said, suggesting that this may be due to more highly qualified staff teams.
Nurseries involved in children's centres were of a higher calibre.
Researchers examined the behavioural effect of time spent in centre-based care by studying 810 children in the sample, split between girls and boys.
Their mean age was two years nine months and on average, children started nursery at 18 months, attending for 24 hours a week.
Centre-based provision had both beneficial and detrimental effects. The researchers found that the more hours and days a week children attended, the more confident and sociable they were.
But children who attended for at least 30 hours and/or three days a week were 'more anti-social', and 'more likely to tease other children and call them names' and 'be bossy and need their own way'. Children who attended for 35 hours or more each week demonstrated 'more worried and upset'
behaviours.
It was not the age children started at nursery that was important, but the number of months children attended and the time spent in the nursery.
The report recommends further research to explore the effects of length of day at nursery on children's behaviour, 'in particular, the effects of attending for a small number of long days over a week, as compared to a greater number of short days'.
Download the National Evaluation of the Neighbourhood Nurseries Initiative: Integrated report at www.dfes.gov.uk/research.
* See also page 4
