A team of researchers in the United States might have just cracked one of the biggest mysteries in economics. It's why young men are vanishing, in Australia as well as overseas.

A decade or so back we had a good idea of where they were. Of the Australian men aged 15 to 24 who weren't in school or higher education, an impressive 85 per cent were working.

That was back in May 2007. By May this year it had fallen to 78.6 per cent. That's one in every five young men not in education now not working, up from one in every seven a few years back. An extra 51,000 young men have "gone dark", slipped under the statistical radar.

And hardly any women. Young women not in education are about as likely to work as they used to be.