Language is the means by which we obscure our meaning without necessarily intending to. That, at least, is the lesson that many medical consultations teach. The doctor thinks he is explaining things to the patient in words of one syllable, the patient believes the doctor has spoken to him in incomprehensible technical jargon. The doctor thinks he is replying to a patient's question, the patient believes the doctor is refusing to answer.

And so on and so forth. The misunderstanding is mutual - it isn't just the doctor who fails to understand. I have overheard many conversations in trains and buses regarding medical matters, and words are attributed to doctors that no medical man or woman could possibly have uttered. "The doctor says I've got a cardiac heart," for example, seldom fails to elicit clucks of the deepest sympathy and commiseration. And when doctors ask their patients what another doctor has said to them during a previous consultation, the answer is often a soup of polysyllabic malapropisms, completely devoid of medical meaning. Doctor and patient, then, are often engaged in a nonsensical dialogue.

One possible way for communication between doctor and patient to improve would be for the patient to write down the questions he wants to ask the doctor but almost always forgets in the heat of the moment. The National Audit Office, for example, has recently suggested 19 questions that a patient who is about to undergo a hip replacement operation might usefully ask the surgeon. With a little adaptation according to circumstances, the questions could be asked by patients who are about to undergo other medical or surgical procedures.

The NAO advises patients about to have hip replacement to ask the surgeon how many such operations he or she performs per year. This is because, naturally enough, surgeons who do a lot of hip replacements tend to get better results than those who do few. Since there is no point in asking a question unless the answer has some practical consequence, the diligently inquisitive patient will be condemned to quite a lot of further research.

For example, how will he know whether the surgeon is telling him the truth? Some surgeons might inflate the figure to pacify patients and to appear more experienced than they are; others might underestimate the figure in order to put the patient off (for orthopaedic surgeons are rarely without sufficient work to do). Yet others might genuinely make a mistake in their answer.

Suppose the surgeon performs 15 such operations per year: is this many or few? To answer the question the patient will have to discover what the average for orthopaedic surgeons is, not just in the country as a whole but in the region in which they can reasonably expect to have their operation, and this is unlikely to be an easily obtainable piece of information.

Let us suppose, however, that the patient succeeds in discovering that the surgeon to whom they were first referred performs fewer operations than average. What do they do then? Go to another surgeon, of course.

Perhaps the NAO thinks it is the easiest thing in the world for patients to switch orthopaedic surgeons at the drop of an answer, but if so it is living in a fantasy world completely free of the information it is supposed to be gathering. It is the Audit Office, therefore, that badly needs auditing, not the orthopaedic surgeons.

In many parts of the country, it takes months to consult an orthopaedic surgeon in the first place, by which time patients are quite like voters in safe seats - they take whatever is proposed. The last thing they will want to do is start to wait for months all over again.

But even if they could go to a surgeon who performed more than an average number of hip replacements, would not his waiting list be extended very considerably by all the people needing a hip replacement who had discovered precisely the same information? And how would surgeons ever be trained, if no one ever wanted to go to a surgeon who had performed fewer than a given number of operations? Even the surgeon who has done more of these operations than anyone else in the world - who exists somewhere - must once have done his or her first, second and third operation. No one starts their career by having done more than an average number of operations.

So the potential patient will end up having to trade the desirability of being operated upon by a surgeon with above average experience with the desirability of being operated upon by a surgeon of lesser experience sooner rather than later.

The NAO likewise suggests that patients ask their surgeon for his results. Unfortunately, it is quite difficult to compare results, because it is absolutely vital - for the com parison to be valid and thus to yield useful information - to compare like with like. This is much easier said than done. The age, sex, social class, extent of the original condition, smoking history etc must be controlled for. And patients have to be aware that a 20% increase in a common complication might be far more significant, from the point of view of their personal safety, than a threefold increase in a very rare complication. Furthermore, not all complications are equal: some are serious, others are relatively trivial. Patients must understand and take this into account if they are to make any sense of the information they ask for.

It is a modern misconception that the more information we have, the better the decisions we take. But in fact, a surfeit of information can obscure reality as much as reveal it; and if in practice we cannot act upon the information we possess, it will only make us bitter and resentful.

With regard to hip replacements, the real problem is not that there are orthopaedic surgeons whose performance is below average - as there must be, once the ineradicable variation of human performance is admitted - but that there are too few orthopaedic surgeons to do the work in the first place. The NAO is in effect a front organisation to distract the public's attention from this lamentable fact, and from the government's failure (and not just the present government's failure) to find a healthcare policy to solve the problem.

As a doctor, I find patients who come with written lists of questions both intimidating and irritating, for they seem little better able to assess the significance of the information they are given in reply than are the people I overhear in the train or bus; and as a patient, on the few occasions when I have been seriously ill and in need of medical attention, the last thing I wanted was information about the relative merits of doctors and their medical procedures. I just wanted to hand myself over to other people and let them sort me out. And so far, at any rate, they always have.