# The awkward mathematics of booms and bubbles

When short and long aren't opposites.

One of the most common responses in the many, many comments to my pieces on Bitcoin over the last couple of weeks has been to ask me why, if I'm so sure it's a bubble, I don't short it.

The simplest answer is that journalism isn't a career which leaves a huge amount of money left over after the bills are paid with which to gamble, and that I'm not entirely sure it's ethical anyway. There's also the fact that the two main Bitcoin meta-exchanges aren't particularly liquid, which leaves me doubtful that I'd get the best value for money on any shorting contract,

Then there's the problem that being pretty certain the bubble is going to pop doesn't leave me any surer about when it's going to pop – something which most methods of shorting require you to know.

Shorting usually involves borrowing the thing you want to short for a fixed amount of time, selling it straight away, and then buying it back just before your loan is up. Ideally, the commodity has dropped in value, and so you make a profit by you pocketing the difference.

In a normal commodity, going short and going long – buying the commodity to sell at a higher price – are roughly symmetrical. If a share in Apple goes up \$1, the people who are long make a dollar a share; if it goes down, the people who are short do.

But that symmetry breaks down when you're dealing with a commodity on the sort of parabolic trend that Bitcoin is shooting along now.

If I spend £100 on Bitcoin, then the most I can lose is £100. Conversely, if the trend continues, I could have £1000 in a month. And the maximum possible payoff is basically uncapped. Suppose I'm catastrophically wrong, and Bitcoin becomes the world currency by the end of the year – anyone who'd bought in to it, even at today's inflated prices, would be a millionaire.

But what if I short it, by borrowing £100 of Bitcoin? Well, then the most I can earn is £100, if the price drops to zero. But the amount I could lose is potentially uncapped, for the exact same reasons that make buying in to it so appealing.

That lack of symmetry – which is an innate feature of, well, maths – serves only to goose the bubble higher and higher. And at the other side, when the down swing comes, it will be vicious; with no shorters ready to step in and buy the coins of people trying to cash out, the volatility will have nothing dampening it.

So that's why I'm keeping my money where it is. But don't think I'm not pretty damn confident when I say that if I had any extra, it still wouldn't be in Bitcoin.

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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# The science and technology committee debacle shows how we're failing women in tech

It would be funny if it wasn’t so depressing.

Five days after Theresa May announced, in her first Prime Minister’s Questions after the summer recess, that she was "particularly keen to address the stereotype about women in engineering", an all-male parliamentary science and technology committee was announced. You would laugh if it wasn’t all so depressing.

It was only later, after a fierce backlash against the selection, that Conservative MP Vicky Ford was also appointed to the committee. I don’t need to say that having only one female voice represents more than an oversight: it’s simply unacceptable. And as if to rub salt into the wound, at the time of writing, Ford has still not been added to the committee list on parliament's website.

To the credit of Norman Lamb, the Liberal Democrat MP who was elected chair of the committee in July, he said that he didn't "see how we can proceed without women". "It sends out a dreadful message at a time when we need to convince far more girls to pursue Stem [Science, Technology, Engineering and Mathematics] subjects," he added. But as many people have pointed out already, it’s the parties who nominate members, and that’s partly why this scenario is worrying. The nominations are a representation of those who represent us.

Government policy has so far completely failed to tap into the huge pool of talented women we have in this country – and there are still not enough women in parliament overall.

Women cannot be considered an afterthought, and in the case of the science and technology committee they have quite clearly been treated as such. While Ford will be a loud and clear voice on the committee, one person alone can’t address the major failings of government policy in improving conditions for women in science and technology.

Study after study has shown why it is essential for the UK economy that women participate in the labour force. And in Stem, where there is undeniably a strong anti-female bias and yet a high demand for people with specialist skills, it is even more pressing.

According to data from the Women’s Engineering Society, 16 per cent of UK Stem undergraduates are female. That statistic illustrates two things. First, that there is clearly a huge problem that begins early in the lives of British women, and that this leads to woefully low female representation on Stem university courses. Secondly, unless our society dramatically changes the way it thinks about women and Stem, and thereby encourages girls to pursue these subjects and careers, we have no hope of addressing the massive shortage in graduates with technical skills.

It’s quite ironic that the Commons science and technology committee recently published a report stating that the digital skills gap was costing the UK economy £63bn a year in lost GDP.

Female representation in Stem industries wasn’t addressed at all in the government’s Brexit position paper on science, nor was it dealt with in any real depth in the digital strategy paper released in April. In fact, in the 16-page Brexit position paper, the words "women", "female" and "diversity" did not appear once. And now, with the appointment of the nearly all-male committee, it isn't hard to see why.

Many social issues still affect women, not only in Stem industries but in the workplace more broadly. From the difficulties facing mothers returning to work after having children, to the systemic pay inequality that women face across most sectors, it is clear that there is still a vast amount of work to be done by this government.

The committee does not represent the scientific community in the UK, and is fundamentally lacking in the diversity of thought and experience necessary to effectively scrutinise government policy. It leads you to wonder which century we’re living in. Quite simply, this represents a total failure of democracy.

Pip Wilson is a tech entrepreneur, angel investor and CEO of amicable