If you've got lucky, it's easy to convince people you're a sage

"Expert" predictions only need a few lucky guesses, then everyone believes them.

LSE's Nattavudh Powdthavee and Nanyang University's Yohanes E. Riyanto presented a paper last month titled Why Do People Pay for Useless Advice? (pdf) The authors demonstrate that people are prepared to pay for investment advice which they know cannot possibly be based on any real evidence – provided the advisor has got things right in the past.

Participants in the experiment were told to bet on five consecutive rounds of coin flips (they could pick the stake, provided it was higher than a minimum level and wouldn't make them lose all their money before the last round). Since they were using a fair coin, the chance of heads or tails coming up each time was 50-50, and the chance of someone calling the correct flips in all five rounds is one in thirty two. More importantly, no amount of expertise can help one predict the outcome of a sequence of coin tosses.

So when the participants were offered the chance to buy "predictions", you would expect them to ignore them. And most of them did, at least for round one (although even then, around 15 per cent of them did pay). But after the first round of tosses, everyone got to see their predictions, even those who hadn't paid. And for half the participants, those predictions were correct. Still, it's obviously just chance, right?

Apparently not so obvious. Those who got a correct "prediction" in round one were three times more likely to pay for one in round two than those who'd got an incorrect one. And by the time a subset of the group had got four correct predictions in a row, the possibility that they would buy a prediction for the fifth round had risen from 15 to 40 per cent.

In other words, just a few lucky guesses are all it takes to get people to pay for what the authors call "transparently useless advice". As they conclude:

Our experiment accurately describes how the real "false" experts typically operate in the information market, and the findings of this paper help to highlight how easy it is for an average person to form a belief in an expert when none may actually exist. 

Something worth bearing in mind next time you are looking at horse tips, stock pickers, or hedge funds, maybe.

George Bush tosses a coin. Is he an expert? Photograph: Getty Images

Alex Hern is a technology reporter for the Guardian. He was formerly staff writer at the New Statesman. You should follow Alex on Twitter.

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When it comes to the "Statin Wars", it's the patients I pity

Underlying the Statin Wars are two different world-views: the technological and holistic.

September saw the latest salvos in what has become known in medical circles as the Statin Wars. The struggle is being waged most publicly in the pages of Britain’s two leading medical journals. In the red corner is the British Medical Journal, which in 2014 published two papers highly critical of statins, arguing that they cause far more side effects than supposed and pointing out that, although they do produce a modest reduction in risk of cardiovascular disease, they don’t make much difference to overall mortality (you may avoid a heart attack, only to succumb to something else).

In the blue corner is the Lancet, which has long been the publishing platform for the Cholesterol Treatment Trialists’ (CTT) Collaboration, a group of academics whose careers have been spent defining and expounding the benefits of statins. The CTT was infuriated by the BMJ papers, and attempted to force the journal to retract them. When that failed, they set about a systematic review of the entire statin literature. Their 30-page paper appeared in the Lancet last month, and was widely press-released as being the final word on the subject.

A summary would be: statins do lots of good and virtually no harm, and there really is no need for anyone to fuss about prescribing or taking them. In addition, the Lancet couldn’t resist a pop at the BMJ, which it asserts acted irresponsibly in publishing the sceptical papers two years ago.

Where does all this leave the average patient, trying to weigh up the usefulness or otherwise of these drugs? And what about the jobbing doctor, trying to give advice? The view from no-man’s-land goes something like this. If you’ve had a heart attack or stroke, or if you suffer from angina or other conditions arising from furred-up arteries, then you should consider taking a statin. They’re not the miracle pill their proponents crack them up to be, but they do tip the odds a little in your favour. Equally, if you try them and suffer debilitating side effects (many people do), don’t stress about stopping them. There are lots more effective things you could be doing – a brisk daily walk effects a greater risk reduction than any cholesterol-lowering pill.

What of the millions of healthy people currently prescribed statins because they have been deemed to be “at risk” of future heart disease? This is where it gets decidedly murky. The published evidence, with its focus on cardiovascular outcomes alone, overstates the case. In healthy people, statins don’t make any appreciable difference to overall survival and they cause substantially more ill-effects than the literature suggests. No one should be prescribed them without a frank discussion of these drawbacks, and they should never be taken in lieu of making lifestyle changes. Smoking cessation, a healthy diet, regular modest exercise, and keeping trim, are all far more important determinants of long-term health.

Underlying the Statin Wars are two different world-views. One is technological: we can rely on drugs to prevent future health problems. This perspective suffers substantial bias from vested interests – there’s a heck of a lot of money to be made if millions of people are put on to medication, and those who stand to profit make huge sums available to pay for research that happens to advance their cause.

The other world-view is holistic: we can take care of ourselves better simply by living well, and the fetishising of pharmaceutical solutions negates this message. I have great sympathy with this perspective. It certainly chimes with the beliefs of many patients, very few of whom welcome the prospect of taking drugs indefinitely.

Yet the sad truth is that, irrespective of our lifestyles, we will all of us one day run into some kind of trouble, and having medical treatments to help – however imperfectly – is one of mankind’s greatest achievements. In arguing for a greater emphasis on lifestyle medicine, we must be careful not to swing the pendulum too far the other way.

Phil Whitaker’s latest novel is “Sister Sebastian’s Library” (Salt)

This article first appeared in the 20 October 2016 issue of the New Statesman, Brothers in blood