Britain's Institute of Physics last month announced that it intends to pay impoverished undergraduates to study physics. By doing so, it hopes to reverse two UK trends. The number of British students taking physics is falling, while student debt in the country is growing — it has risen by 43% since 2000, according to market-research company MORI. David Wallace, the institute's president, sees physics as a core discipline that is integral to Britain's knowledge economy. He hopes that providing students with an annual grant of £1,000 (US$1,800) during their undergraduate course might encourage more to pursue the discipline.

But could this scheme not be extended? Physics isn't the only discipline facing a student shortfall in the Western world, and Britain isn't the only country where students are becoming increasingly burdened by loans. In the past few years, mathematics and chemistry have also seen a decline in student numbers — not just in Britain, but in the United States and much of mainland Europe.

Sam Rankin, director of the American Mathematical Society's Washington office, says that he is unsure whether money alone is the answer. Students care about debt, he says, but most weigh the cost of that debt against the benefit of the career it buys. They want to know what kind of job they will get after spending all those years studying, Rankin notes.

Providing cash incentives for students to move into neglected disciplines can make sense. But gathering career data and disseminating them to prospective undergraduate and graduate students will help them to choose whether their course will be a good career investment. Of course, such information could be dangerous — discouraging data might prove to be the equivalent of paying a student £1,000 not to pursue a particular discipline.