The Institute of Education at London University analysed OECD education surveys and UNESCO data from 33 countries. It found that while early years education does raise children's attainment levels at age 15, there is no evidence to suggest that it helps disadvantaged children more than their peers.
The analysis, by Professor Andy Green and Dr Tarek Mostafa, found no apparent relationship between pre-school participation rates and social gaps in pupils' later reading performance.
Professor Green said, 'Pre-school education benefits children from all social groups but does not appear to close the gap. There is no relationship between levels of participation in pre-school education and care at 15 and their attainment.'
He admitted that he had been surprised at the findings, because the researchers had expected the analysis would show that children from poorer families made greater gains than their peers.
'The assumption in the literature is very strong and we would expect disadvantaged children would benefit more and catch up. All children benefit roughly equally.'
The analysis also showed that children from better-off families were more likely to participate in early years education than poor and immigrant families, even in Scandinavian countries where participation is typically high across social classes.
'Our findings suggest that pre-school education will only help to close these gaps at 15 if children from less advantaged backgrounds receive either more, or better quality, provision,' said the researchers. 'This is a tall order, since even the Scandinavian countries do not seem to have achieved this. In fact, with the rolling back of the Sure Start programme, the chances of lower income families accessing high quality pre-school education in this country are likely to diminish.'
The study also found that pre-school education leads to higher employment among women.
The researchers analysed education and employment data for 16 countries and calculated that, on average, a 10 per cent rise in pre-school education attendance led to a 6 per cent rise in female employment.
Professor Green said, 'The data shows a strong economic argument for pre-school education.'
Professor Green, director of the Centre for Learning and Life Chances in Knowledge Economies and Societies (LLAKES), presented the paper, 'Pre-school education and care - a win-win policy' at the ECER conference in Berlin last week.