Robert Peston says that the OECD's report on the low level of young English adults' numeracy and literacy skills has "worrying implications about the long-term potential of the British economy." This skates over an awkward fact - that, in international data, it's difficult to find a strong link between human capital and economic growth.

As Bryan Caplan says, most coefficients of the impact of education on GDP are "very low." He's not the only sceptic. So is Alison Wolf. So is Torge Middendorf, who says the link between human capital and GDP is "fragile". And a survey by Krueger and Lindahl's found (pdf) that:

Education was statistically significantly and positively associated with subsequent growth only for the countries with the lowest level of education...
For countries with a high level of education growth was typically inversely related to the level of education.

Why might this be? One possibility is measurement error; measures of national educational attainment are unreliable, and in richer countries, there just isn't much cross-country variation in long-run growth. But there are other possibilities:

1. Signalling. My education has made me richer. But it's done so by getting me well-paid jobs at others' expense. This hasn't obviously raised national income. As Bryan says, there's a rat-race element to education.

2. Institutions matter more. Years ago, P.J O'Rourke wrote:

Why do some places prosper and thrive while others just suck? It's not a matter of brains. No part of the earth (with the possible exception of Brentwood) is dumber than Beverly Hills, and the residents are wading in gravy. In Russia, meanwhile, where chess is a spectator sport, they're boiling stones for soup.

Why, then, is Beverly Hills richer than Russia? It's because the US has had insitutions favourable to growth - freeish markets and a nodding acquaintance with the rule of law - whilst Russia hasn't.

3.Mismatch. More education can lead to over-education, to graduates being baristas.

4. Deterring investment. A large pool of workers with basic skills would bid down wages of low-skilled jobs - which is why the CBI is so keen on improving literacy and numeracy. But low wages might deter firms from investing in labour-saving equipment and techniques, which might reduce long-run growth.

Now, I don't say all this to advocate less education, but simply to question the instinctive belief that relatively low skills will consign the UK economy to weak growth; it's probably other things that'll do that.

Instead, we should perhaps worry for another reason - that learning is a good thing in itself, regardless of its economic impact. But such a view is far outside the Overton window.