If you could be given a money substitute for charming nurses, how much would compensate you for their absence?

At the heart of the clinical practice of medicine is the idea of a 'trade-off' - we prescribe a drug, juggling the downside of the side-effects with the upside of the treatment benefits.

Perhaps one source of conflict between managers and doctors is a common misapprehension over this notion of the 'trade-off'. It seems to managers, for example, that doctors have difficulty grappling with the trade-offs implicit in any change.

This can be seen in the impoverished way the health service has tried to measure patient preferences. However, the measurement of attitudes and values associated with healthcare will inevitably remain a critical issue.

The problem is that most attitude measurement in the NHS simplistically probes what patient views are without considering two crucial social psychological issues - first, patients may be loath to tell you directly what they really think and second, their attitudes only make sense in as far as they appreciate the implicit trade-offs involved.

For example, charming nurses may not turn out to be quite so vital to patients if it was understood that this benefit could only be bought at the expense of numbers of nurses.

This more realistic concept of preferences comes from economics, where preferences are defined as individuals' 'utility' for consuming healthcare goods and services. The assumption is that we aim to maximise our utility. Economic theory argues that utilities or benefits can be measured in money-equivalence.

In other words, the real strength of preferences is the monetary compensation that would leave people indifferent between having a given utility change and not having the change: that is, willingness to pay or willingness to accept.

If you could be given a money substitute for charming nurses how much would compensate you for their absence? This figure, in comparison with the monetary value for what you would accept to forego clean waiting rooms, tells us which you really prefer.

In the commercial sector the idea that you cannot have everything seems self-evident but in the NHS it looks as though we are chasing our tails so often because patients' true attitudes and preferences have not been properly measured or understood.

Sometimes patients hold inconsistent attitudes. Then attempting to provide a service which ticks all the boxes is impossible. Managers should be measuring attitudes more carefully, or providing leadership and judgement - perhaps we only discover what our attitudes and preferences really are when they have been articulated by an insightful other.