Friday, 19 September 2008

How expert is an expert?

We are forever having the opinions of experts thrust at us on television, radio and the internet. Experts are very useful to those making programmes for popular consumption because they stifle debate. Once an expert has pronounced there is no need for the presenter to explain, the expert's word is law. But then a problem arises because a debates is presented between experts. What a curious concept, one might think, if they are experts they must know the truth, therefore what are they debating?

The reality is that an expert is simply someone who is believed (or believes himself) to know more about a subject than the person to whom he is offering his opinion. In some fields expertise comprises knowledge of facts, for example the cricket scorer and statistician Bill Frindall stores vast amount of information about past international cricket matches in his head and is, therefore, an expert in that area of factual knowledge. Not all expertise is based on knowledge of facts, however, some is based on physical skills (Kevin Petersen is an expert batsman), some on the ability to interpret information in order to predict what is likely to happen in the future (Sir Ian Botham is an expert on how a cricket pitch will play during a match) and some on the ability to guide others to take a path of benefit to them (Peter Moores is an expert cricket coach). Keeping with the cricket theme, there are many other expert batsmen, pitch interpreters and coaches none of whom will agree with any of the three I have named about everything. They are all experts because expertise does not give total knowledge or a monopoly of wisdom.

A week ago I gave my "take" on the trial of those accused of criminal damage of a power station (would add a link but don't know how). In the comments someone questioned whether two "expert" witnesses should have been allowed to give evidence. The general rule is that an expert witness can be called where the case involves an issue which cannot be decided without assistance from someone with specialist knowledge or skills which the judge or jury is unlikely to have (this is a gross generalisation, there are many ifs and buts). A simple illustration could be a case in which a solicitor is accused of having made a mistake when undertaking a conveyancing transaction. If the trial is heard by a jury it would be normal for an experienced solicitor to be called to explain how conveyancing should be done whereas a judge would not require such assistance.

No special paper qualifications are needed to be an expert in court, knowledge or skill acquired through experience can be enough. Perhaps the best example I know of an expert without formal qualifications is the astronomer Sir Patrick Moore, some of his work has been at the forefront of his science for decades yet he had no university degree when he started writing and broadcasting. The absence of a piece of paper with a crest on it and the signature of a Vice-Chancellor did not stop his maps of the moon being used by NASA during the Apollo space programme.

Sometimes the finest paper qualifications in the country are no bar to someone being completely wrong in the area to which he has dedicated his life's work. Professor Sir Roy Meadow was pre-eminent in the field of infant death. He identified a syndrome which led to children being killed by those with care of them and a number of people were convicted of murder on the basis of his expert evidence. His theory also led to countless children being removed from their parents and placed in care. Meadow's expertise was not in a matter of knowledge or facts, like cricket statistics, but in the interpretation of facts. His personal expertise was no stronger than the theory he promulgated. On that theory being discredited thoroughly, so was he; having caused immeasurable suffering to others. There was no evidence that he acted through spite or said things he did not believe, it is just that his pet theory was his life. It became a personal obsession such that he was unable to accept any criticism of it. He knew he was right, he knew he was doing good, he knew there was no doubt.

The late actor and raconteur Kenneth Williams often made a quip about experts who concentrate and refine their specialisation so that over time they "know more and more about less and less". This can be a very good thing in the right hands and result in groundbreaking and beneficial advances in many fields. In the wrong hands it can turn expertise into a dangerous obsession with the expert being placed on a pedestal and critics being dismissed as unqualified to challenge the great man or corrupt through envy.

Meadows was finally undone by a single answer he gave in evidence. When asked the probability of there being two accidental infant deaths (often referred to as "cot deaths") in the same family he gave the figure 73,000,000:1. This was such a startling statistic that it raised eyebrows in many quarters and was the start of the eventual total unravelling of his theory, his reputation and his career. Those convicted on his evidence alone were released if still in prison but the children taken from their parents had grown up or settled with a new family, for them it was too late to put right the wrong that had been done to them.

It is rather a strange concept that one person's theory could have such wide-spread consequences, although not so strange when one looks at the context. Sudden infant deaths have occurred for as long as anyone can remember. Baby was put to bed and died. No one knew why, yet it was such a highly emotive topic that everyone wanted an explanation. If there was an identified cause it might be possible to do something to prevent it happening to another family and even if the cause was not preventable at least we would know what it was. Roy Meadow filled the void. His theory was plausible and could not be positively disproved, it became the accepted knowledge which made it even harder to disprove. With every child taken away and every mother or nanny convicted of murder he was given more support, the court accepted the theory therefore it was no longer just a theory it had been proved to be true. But it was not true, it was just another of the thousands of false theories thrown up in science over the years.

Beware the single-issue expert with a pet theory.


Mark Wadsworth said...

I'm not an expert and I have several pet theories. Does that mean I'm wrong all the time?

TheFatBigot said...

Not necessarily. Many a non-expert pet theory based on common sense is much more sound than an expert one based on ego trippery.

fewqwer said...

Another thought-provoking article, thanks FB.

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