What is a gap year worth?
Gap-year travel overseas may not be broadening the minds of young people but confirming their misconceptions of other cultures.
Their volunteer work may also be benefiting them more than the people they are supposed to be helping, according to research presented to the Royal Geographical Society.
But gap-year companies and advisory organisations insist that a well organised "year out" - as opposed to a "year off" - benefits students, the communities they work in and the UK economy.
Newcastle-upon-Tyne university doctoral student Kate Simpson said gap-year travel had turned into an industry, offering a "training ground for future professionals" rather than an idealistic opportunity to see the world, if not save it.
Ms Simpson spoke to around 35 18 to 19-year-olds travelling in Peru between finishing school and starting university. One admitted doing voluntary work "for something that would look good on my CV".
Many blue-chip employers now look for gap-year activity in job applications from young graduates, but the work undertaken by travellers can be of questionable value.
Travel companies focus in their brochures on "making a difference". But the projects they endorse often reinforce old-fashioned westernising models of development - with enthusiastic but amateurish young people doing things to communities, rather than enabling communities to identify their own needs.
One student wondered whether her work with vulnerable children in Lima had benefited them or "is it just us forcing ourselves on them for our own experience?"
But generally students talked about how lucky they were to have these opportunities, without questioning underlying issues, such as inequality or their own preconceptions about the "happy poor".
Another student, who spent a month in a shanty town, concluded: "We expect a lot whereas they don't have TVs - but it doesn't bother them because they don't expect one."
Ms Simpson said: "Industry is using these experiences as a training ground.
"I'm questioning what sort of global citizenship that means if our young people can go out and experiment in other people's countries."
Richard Oliver, chairman and chief executive of the Year Out Group, a not-for-profit association of gap-year organisations, insisted that a well-structured and well-researched gap year benefited all involved.
He said that the majority of overseas hosts are thrilled with the work the young people do. "I think the UK benefits as well because it has a better informed and better skilled workforce," he said.
However, he said, students need to think carefully about the value of their volunteer work.
Companies offering shorter placements as part of a travel package were responding to changing customer demand for "two weeks here, two weeks there" rather than longer, more substantial placements.
But the variety of placements available is a strength of the sector, he said.
"Dropping out or signing up? The professionalisation of youth travel," by Kate Simpson. email@example.comSee www.yearoutgroup.org