My colleagues and I recently published an article in the Journal of Public Money and Management questioning Treasury claims that the government's private finance initiative (PFI) programme saves money and is cost effective. As it's had rather a lot of press coverage, Andy Kerr, the Health Minister, was moved to put out a statement to the media.

Instead of addressing the evidence we meticulously assembled, he says he "will not take lessons on renewing Scotland's public services from biased academics who seek to mislead the public with outdated and discredited arguments".

It's not a very impressive answer. In our article we offer no lessons on renewing Scotland's public services.

All we do is scrutinise the basis on which the Treasury claims to have made its decisions. To call us biased academics who seek to mislead the public is a slander.

It also constitutes an unnecessary impoverishment of public debate. A recent poll of senior academics found that almost 80% of those surveyed felt that academic freedom ("speaking truth to power") was being sacrificed to a culture of "bully and blame" (see the Times Higher Education Supplement, October 27, 2006). Mr Kerr's statement is the sort of thing they were talking about. The shadow minister for Higher Education in England, Boris Johnson, got it right when he observed that "the most worrying thing is that academics should be inhibited from saying things they think may be displeasing to their ultimate political masters. But they should not have ultimate political masters".

Just so. I can understand the minister being angry that the facts revealed by our research do not help him politically, but fulminating against this is no way to deal with it.

Openness and transparency are surely the key to winning people over to your point of view? If the public knew the facts, and the facts supported the decision to use the PFI, they would surely be won over. As it is, a BBC Scotland poll published earlier this week found that "building and running state schools and hospitals through public bodies is the top priority for Scottish voters".

Could I offer a friendly pointer for where Mr Kerr might begin? He recently signed off funding for a new private-sector treatment centre in Stracathro, but neither the "value for money" data used to inform that decision nor the contract have been disclosed to the Scottish Parliament or the public. Publish them now. Using the Freedom of Information Act, I've tried to obtain data on how PFI payments break down in major Scottish schemes. In England some of these data are in the public domain. But Mr Kerr's ministry has withheld the data. Again, why? Publish the data and let people see whether he did the right thing.

Democracy is negated when public expenditure data are concealed under the cloak of "commercial confidentiality", or, indeed, when politicians simply refuse to release them. In the future, I hope Mr Kerr will do all he can to ensure that all these data are open to scrutiny.

In the meantime, I look forward to civilised, non-personalised and, above all, evidence-based exchanges with the minister. - Professor Allyson M Pollock, Director, Centre for International Public Health Policy, University of Edinburgh, Medical Quad, Teviot Place, Edinburgh.