There is no proof that the leadership courses run by the Columba 1400 centre on the Isle of Skye bring long-term benefits to schools, according to an education expert.
Walter Humes, professor of education and associate dean at the University of the West of Scotland, acknowledged that Columba 1400 programmes were "hugely rewarding on a personal level", but claimed the organisation had failed to "establish convincingly" whether taking part in its activities had any "long-term systemic benefits" for schools.
"For that to be established, you need more than self-reporting; you need a proper evaluation from colleagues," he said.
"It's an alternative view of training and it has huge personal benefit, but I'm less convinced of the long-term systemic benefits."
Professor Humes also criticised the involvement of entrepreneurs such as Sir Tom Hunter in education. Selling trainers, Professor Humes suggested, was quite different from educating young people.
"My other concern," he said, "is the democratic basis for the involvement of very rich people in education. Members of the Smith Group (the schools-business partnership set up by the former First Minister, Jack McConnell, and endorsed by the SNP Government) were appointed using the patronage system - someone taps you on the shoulder and you're in. There are issues about the democratic nature of that kind of appointment."