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.

Grant Shapps on the campaign trail. Photo: Getty
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Grant Shapps resigns over Tory youth wing bullying scandal

The minister, formerly party chairman, has resigned over allegations of bullying and blackmail made against a Tory activist. 

Grant Shapps, who was a key figure in the Tory general election campaign, has resigned following allegations about a bullying scandal among Conservative activists.

Shapps was formerly party chairman, but was demoted to international development minister after May. His formal statement is expected shortly.

The resignation follows lurid claims about bullying and blackmail among Tory activists. One, Mark Clarke, has been accused of putting pressure on a fellow activist who complained about his behaviour to withdraw the allegation. The complainant, Elliot Johnson, later killed himself.

The junior Treasury minister Robert Halfon also revealed that he had an affair with a young activist after being warned that Clarke planned to blackmail him over the relationship. Former Tory chair Sayeedi Warsi says that she was targeted by Clarke on Twitter, where he tried to portray her as an anti-semite. 

Shapps appointed Mark Clarke to run RoadTrip 2015, where young Tory activists toured key marginals on a bus before the general election. 

Today, the Guardian published an emotional interview with the parents of 21-year-old Elliot Johnson, the activist who killed himself, in which they called for Shapps to consider his position. Ray Johnson also spoke to BBC's Newsnight:


The Johnson family claimed that Shapps and co-chair Andrew Feldman had failed to act on complaints made against Clarke. Feldman says he did not hear of the bullying claims until August. 

Asked about the case at a conference in Malta, David Cameron pointedly refused to offer Shapps his full backing, saying a statement would be released. “I think it is important that on the tragic case that took place that the coroner’s inquiry is allowed to proceed properly," he added. “I feel deeply for his parents, It is an appalling loss to suffer and that is why it is so important there is a proper coroner’s inquiry. In terms of what the Conservative party should do, there should be and there is a proper inquiry that asks all the questions as people come forward. That will take place. It is a tragic loss of a talented young life and it is not something any parent should go through and I feel for them deeply.” 

Mark Clarke denies any wrongdoing.

Helen Lewis is deputy editor of the New Statesman. She has presented BBC Radio 4’s Week in Westminster and is a regular panellist on BBC1’s Sunday Politics.