Copying from the Telegraph

Polly Toynbee's column today is relatively fact-free (well, they always are, but at least this time there aren't a lot of non-facts masquerading as facts). however, she does say:

Indeed, recent research on child care found that children left with grandparents all day did worse than children in good nurseries.

As ever with Pollyanna, there is no source, but at a guess she is referring to an article called "The Effects of a Mother's Return to Work Decision on Child Development in the UK" by Paul Gregg, Elizabeth Washbrook, Carol Propper and Simon Burgess, published in the Economic Journal of February 2005 (pdf of the article is available here at the time of writing). The article does not distinguish between care provided by "grandparents" and "good nurseries" -- it distinguishes among: informal unpaid care by a relative; non-relative paid care; and centre-based care. The research finds that relying on unpaid care by a relative (as opposed to paid care) is detrimental to children where the mother returns to work when her child is 18 months old or younger, though only, bizarrely, in better off households. Why? Difficult to say. Quote from the article:

We conclude that the use of predominantly relative care is damaging only for children in the more advantaged households and that children in less advantaged households are not harmed by early full time maternal employment. However, we are unable to say much about the reason underlying this result.

This is so far from Toynbee's inaccurate précis that you would certainly be entitled to ask why I think that this is the research to which she is alluding. Fair question. It rather seems as if the mangling starts, strangely enough, in the Telegraph. In this column, their social affairs correspondent Sarah Womack summarises the research thus:

Mothers who return to work part-time when their children are as young as three months old have no adverse effect on the future development of their offspring, according to the latest academic survey.

But full-time working mothers who leave their children under 18 months old in the sole care of grandparents or of friends risk seeing their children fall behind at school.

Researchers say there are "significant" detrimental effects when the child is left with an unpaid carer.

The child is, on average, three months behind his or her peers by the age of seven, doing less well in literacy and numeracy tests and being less adept with language.

If the child goes to a nursery rather than grandma's while his or her mother works full-time, he or she is about one month to two months behind by the age of seven.

Note that it starts as an accurate synopsis -- the second paragraph is not bad (though "of grandparents or of friends" is not the same as "relatives" -- the authors of the article talk about, for example, partners providing care). However, by the final paragraph of the quote Womack is trying to give examples and straying dangerously from the research she is trying to summarise. However, she is not straying as badly as Toynbee's sloppy, innacurate one-sentence summary.