« Full employment, capitalism - and beyond | Main | Johnson's appeal »

June 10, 2021


dilbert dogbert

This old and obsolete engineer says the question “a piece of string is wrapped tightly around the Earth. In order for the string to be lifted an extra metre in each direction, roughly how much longer would it need to be?”
IS UNDEFINED!!! how is the string wrapped? North South Pole to Pole? Wrapped at the equator or wrapped at some latitude?
Define "each direction". East, West, North South or vertically from the center of the earth. The x, y, z coordinates? What unobtainium material is the string made of??? If infinitely stiff, the string could not be moved.
Silly question and my questions are even sillier.

nick j

that immigration reduces wages has been amply illustrated by the current crop of employers wailing about the "labour shortage" occasioned by brexit and covid. in the absence of desperate immigrants employers will have to improve terms and conditions if they want to attract local labour.

Jan Wiklund

One example where people beat economists was the Euro referendum in Sweden in 2003. Most economists told us it would be a disaster not to be in the euro union, but a majority voted against. And now we know rather well what is wrong with the euro - and Sweden does on the whole better than the euro countries.

I think the economist majority simply were prisons in a neo-classic bubble, where everything that made trade easier was right, with no other questions asked. Not only laymen are simplicists, sometimes.


@nick. But like the man said..."migrant workers also add to demand; any incipient fall in wages raises demand for workers, or cuts prices or interest rates..."

V.M. Smith


. . . fewer than half of students . . .



I had seen the string/earth thing before - the answer is counter intuitive and illustrates the benefit of wide reading and long experience - sometimes. Then we get into assumptions - the earth is a perfectly smooth sphere, no seas or mountains and a perfectly light inextensible string etc etc.

I suppose we all conjure up theories as to why this or that - look at Aristotle on biology - sort of logical but mostly wrong. Only when someone goes and has a close look do better theories come along. Even that depends on how close a look, at what samples and with what background - think phlogiston. We will do anything to make a crap theory look like a good one. Possibly why it takes so long to get a workable theory going.

I like the correlated example. If you want to get a rubbish idea through get the media on your side, get a bit of correlation going. Known as witness tampering in other circles.

Dave Timoney


The trick of the question is to get you to imagine a 3-dimesional, not quite perfect sphere. The trick of the answer is to reduce it to a 2-dimensional circle whose radius is irrelevant. So, using the well-known formula for calculating a circumference ...

(2π(r+1)) - (2πr)

This reduces to: 2π1, or 2 x 3.1415 = 6.283 metres.

It's always best with such puzzles to start by asking: what is misleading or irrelevant in the question? That's the same principle that can be applied to issues such as immigration and fiscal management.


@Paulc156 yes "migrant workers also add to demand" - especially for housing, which is rather inelastic, so property prices and rents go up. Hence even if wages do not decline, workers will have less disposable money in their pockets.

Since 1997 property prices have increased by over 173% in England whereas real incomes for 25-35 year-olds have increased by just 19%.



Well property prices might be inelastic but that doesnt say so much about migrant workers as it does about developers and their land banking on steroids business model and the point blank refusal of government to do what it did for several decades after the war;build homes for social rents.


"The trick of the question [...] The trick of the answer [...]"

Isn't the questioner just trying to confirm their own intuitions about the "wrong by orders of magnitude" intuitions of others?


Nothing beats a good experiment that proves your favourite theory wrong. Back to the quadrille paper and pencil. That seems the trouble with economics, not so easy to go in the lab, knock up an experiment and chuck it in the bin when it fails. Worse still statistics, just cuts the signal to noise ratio a bit whilst adding a whole load of problems. Even the logicians are apt to go wrong very easily. Without a confirmatory experiment you are out on a limb.

Some games plus a few students may be suggestive but you don't usually get to mess with a real economy. Indeed what is an economy - is it maths or sociology or guesswork. Not like the physical sciences - the thing you are looking at changes all the time and indeed really does do its best to confound the experimenter. A great many unknown unknowns and feedback paths and people doing their best to confound the effects.

Interesting to watch the experts trying to understand and practice economics - looks pretty difficult though.


I'm reminded of Fischer Black's unjustly ignored 1986 essay Noise https://onlinelibrary.wiley.com/doi/full/10.1111/j.1540-6261.1986.tb04513.x

"Noise in the form of expectations that need not follow rational rules causes inflation to be what it is, at least in the absence of a gold standard or fixed exchange rates. Noise in the form of uncertainty about what relative prices would be with other exchange rates makes us think incorrectly that changes in exchange rates or inflation rates cause changes in trade or investment flows or economic activity. Most generally, noise makes it very difficult to test either practical or academic theories about the way that financial or economic markets work. We are forced to act largely in the dark."


Jan Wiklund perfectly illustrates the thrust of the article by confusing correlation with cause "One example where people beat economists". Economists did not predict disaster and people may have wanted far more to retain a currency they were perfectly happy with, rather than take a risk on an unproven one. Sweden is ranked a modest 12th among 45 countries in the European region. It has not gained by not being in the Euro. It has made currency exchanges very rich.
"And now we know rather well what is wrong with the euro" - do we? In spite of the criticism it remains one of the World's most stable currencies. UK not being in the Euro has enable Brexit to take place, losing the UK tens of £Bs, and its place in the World, and the £ has sunk against the Euro by around 20% for the last 5 years - that is a huge loss of UK asset valuation and off-putting to any inward investment. France now has UK's former top spot there.

The comments to this entry are closed.

blogs I like

Blog powered by Typepad