Robert Meyer, director of doctoral programmes at Wharton school, University of Pennsylvania, says that, in years past, MBA students tended to roll their eyes in disbelief at the suggestion that they might consider studying for a doctorate.

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The economic downturn, says Prof Meyer, may have provoked a slight shift in such attitudes. Last year, for the first time in some years, Wharton saw an increase in domestic applications for its programme.

Until recently, the majority of applications for doctoral programmes at the school came from overseas, most notably China, although the proportion accepted from overseas is generally about 50 per cent of the annual intake.

"Within the pool of MBA students, the majority want to work in the commercial world, but there are some who are undecided and sit on the fence for a while," says Prof Meyer.

"Now, with weaker job prospects in the traditional recruiting areas for MBAs, it opens this minority's minds to other opportunities, including a career in academia."

He adds the school could virtually promise anybody on its PhD programme that there would be a job at the end of their research. "As of yet, the factors limiting job opportunities in the private sector have not limited jobs for academics."

Wharton has one of the biggest cohorts of doctoral students among business schools.

Doctoral programmes are one measure of a school's scholarship and schools with high numbers include Wharton, along with Warwick Business School and Imperial Management School in the UK where, unusually a majority of PhD scholars go on to pursue careers in the private sector, according to David Norburn, Imperial's dean.

This is because of strong links between the school and the City of London, with companies, including CitiBank, offering scholarships to doctoral students who work on their data.

Similarly, most students on DBA programmes, such as offered by Cranfield School of Management in the UK, are more practical in their approach than most PhD programmes, with participants on Cranfield's part-time four-year programme generally working at senior strategic levels in their organisations.

Many prestigious schools, however, do not run doctoral programmes; these include the Tuck School at Dartmouth College, US, IMD in Switzerland and the McDonough School at Georgetown University, Washington DC.

In some countries, including France, business schools do not generally run doctoral programmes - with HEC, one of the leaders in French business education, a Gallic exception.

However, a number of schools are now actively expanding their provision at a time when there is strong competition for PhD graduates, with a shortage of numbers provoking salary rises.

During the next decade, the US' Duke University's Fuqua school expects to double the number of students undertaking doctoral programmes.

Duke's expansion will follow the construction of a new student centre, which will offer more accommodation for doctoral students at a faculty which is aggressively hiring new staff. Fuqua is already highly research-orientated, with a high percentage of doctoral theses in marketing.

This year, the school is experiencing an increase in applicants - this month, the school is up about 41 per cent compared with the same period last year in its PhD applicants.

The foreign applicant pool is up 32 per cent and the domestic applicant pool is 78 per cent higher. Jim Bettman, professor of marketing, says: "It could be the recession, or the reputation of the school."

Dezso Horvath, dean of Schulich School of Business at Canada's York University, says he had a record number of applicants for last year's places, a development he attributed to the shortage of such qualified staff and strong upward pressures on salaries.

"The fight for talent in business schools is great," he says. The majority of his doctoral alumni work in Canadian business schools, although a significant number are employed in leading US schools.

In Europe, Hubert Gatignon, dean of doctoral programmes at Insead, which admits about 15 new doctoral students a year, says the French school is considering expanding numbers slightly. "There is very strong demand for graduates," he says.

Joan Ricart, associate dean for research and doctoral programmes at Iese in Spain, says it is too early to say whether the economic downturn has had an impact on applications for doctoral programmes at his school.

"There may be a few more enquiries from people in consulting firms, but few of them turn into solid applications because people do not have the academic backgrounds we are looking for," says Prof Ricart.

Iese has about 50 students currently on doctoral programmes, with no immediate plans to expand numbers significantly because, like many other business schools, it has faculty constraints.