Scientific advice? Take it or leave it
The brouhaha surrounding the sacking of Professor David Nutt by Alan Johnson leaves me in two minds.
On the one hand, I think public policy can be enhanced by having the advice of experts. The process of thinking through a problem, adducing relevant evidence and engaging in internal debate with fellow specialists before advice is offered is likely to improve the quality of decision-making. Moreover in this case I am inclined to sympathy with Professor Nutt’s contention that the dangers of cannabis can be exaggerated. Like many IEA supporters, I suspect Britain’s policy towards drugs is bonkers. But that’s another story.
On the other hand, I have some sympathy with Alan Johnson. The scientific issues surrounding drugs policy are not clear cut and in any case are only part of the picture which politicians have to deal with. Rejecting Professor Nutt’s advice in a sensitive area like this is forgivable, and when the Professor went public on the disagreement Mr Johnson was certainly within his rights to tell him to get on his bike.
What I really don’t like is the way that the media artificially set up the idea of all-knowing, altruistic scientists versus venal politicians – which is no doubt why an Evening Standard poll yesterday showed three quarters of those polled supported Professor Nutt.
For experts often go way beyond their brief. Back in a March blog post I drew attention to the proposal by Sir Liam Donaldson, Chief Medical Officer for England and Wales, to impose a minimum price of 50p per unit of alcohol. Sir Liam is a man with a long track record of telling people what to do based on a debatable reading of evidence. Or take the former Chief Scientist, Sir David King, whose pronouncements on climate change and what we ought to do about it were sometimes extremely contentious.
A further consideration is that, even where experts don’t have an axe to grind, the basis for firm and unequivocal pronouncements is tenuous at best. Most medical advice we are given is based on epidemiological studies which often depend on unreliable recall and in the nature of things can never control for all relevant factors. Much advice on diet, for example, doesn’t bear close scrutiny and different studies often produce conflicting results.
Science is a process of conjecture and refutation, and all scientific knowledge is contestable. Any advice based on it should carry clear caveats. Often it will be sensible for policy-makers to take this advice, but we should never give experts the authority to impose it either directly or by appealing to a public opinion which can change with the weather.