Skip to main content

Overripe cherries

The real forbidden fruit - don't pick me!
In science, one of the worst sins is cherry picking. I don't mean it's a bad move for scientists to get themselves some of the fleshy drupes of Prunus avium. They are delicious. The cherry picking in question refers to picking out bits of data that support your hypothesis and ignoring the rest.

A really bad example of cherry picking would be something like an experiment to measure the wibblability of cheese strings. (I can't be bothered to think up a real experiment.) Let's say they are expected to have a wibblability of 12 on the Kraft scale. A series of measurements come up as 8, 12, 7, 7, 13, 6, 8. Not encouraging... unless you only report data points 2 and 5. Naughty - but it happens. It doesn't have to be as explicit as that, though.

Let's imagine you are doing a psychology test that requires considerable concentration. Half way through there is a loud bang in the street. Everyone rushes to the window to see what happened. After a little while they get back to the test and continue. Let's say the current theory suggests outcome A for the test, but it could also have outcome B. So the psychos (sorry, psychologists) mark the test and they get outcome A. Clearly the incident didn't disrupt the test, so they record the data. But now imagine on marking the test they got outcome B. That wasn't expected. So it was probably the disruption that invalidated the test, because the subjects lost concentration. So they discard the data. See what they did then? Subtle cherry picking - keeping data that supported the theory, throwing away data that didn't - but it didn't seem so bad, because they had an excuse.

In politics, the usual approach is far less subtle. Politicians cherry pick all the time, presenting data that supports their case, ignoring data that doesn't. Or in the case of UK government advisor Professor David Nutt back in 2009, firing the scientist if they don't like the data. We almost expect this with politicians - but why? They shouldn't be allowed to get away with it.

However, I would say that we are much more tolerant of cherry picking when it is employed by activists and charities, and we shouldn't be. I'm afraid they too resort to cherry picking, but we tend to just get their message without any attempt to see whether they are only giving us a part of the data. This is true, for instance, of almost all campaigns for and against different forms of power, whether it's wind power or nuclear. But the example that made me write this post is the anti-globalisation movement.

While most of probably don't support the means sometimes used, many people have a sneaking regard for the message of anti-globalisation. We know those big companies (and especially banks) are rapacious uncaring monsters. And some certainly are. We know that poor people in third world countries are being exploited so we can get cheap clothes and electronics and so on. And they are. This is important stuff that needs consideration. However, I really don't think the anti-globalisation people do themselves any favours by the rampant cherry picking they employ. The picture is more complicated.

I'm currently reading a book on the global crisis by the excellent (if sometimes strangely intoning) Robert Peston, the BBC's business editor. (I'll be reviewing it when I've finished.) And he points out what a huge benefit globalisation has been to many, many millions of poor people. The fact is that living standards in the likes of China and India have been improved on a massive scale by globalisation. Frankly most of the population in places that are on the 'sweatshop' end of globalisation had totally terrible lives beforehand. Now what we mustn't do is cherry pick in the opposite direction. There are still those bad sides of globalisation. But what this says to me is that globalisation is not a bad thing - it does a vast amount of good - but that we need to do it better.

This is a message those protestors really ought to learn. Otherwise what they are campaigning for is put over a billion people back into intense poverty. And that's not really what they have in mind, I think.

Image from Wikipedia

Comments

Popular posts from this blog

Why I hate opera

If I'm honest, the title of this post is an exaggeration to make a point. I don't really hate opera. There are a couple of operas - notably Monteverdi's Incoranazione di Poppea and Purcell's Dido & Aeneas - that I quite like. But what I do find truly sickening is the reverence with which opera is treated, as if it were some particularly great art form. Nowhere was this more obvious than in ITV's 2010 gut-wrenchingly awful series Pop Star to Opera Star , where the likes of Alan Tichmarsh treated the real opera singers as if they were fragile pieces on Antiques Roadshow, and the music as if it were a gift of the gods. In my opinion - and I know not everyone agrees - opera is: Mediocre music Melodramatic plots Amateurishly hammy acting A forced and unpleasant singing style Ridiculously over-supported by public funds I won't even bother to go into any detail on the plots and the acting - this is just self-evident. But the other aspects need some exp

Is 5x3 the same as 3x5?

The Internet has gone mildly bonkers over a child in America who was marked down in a test because when asked to work out 5x3 by repeated addition he/she used 5+5+5 instead of 3+3+3+3+3. Those who support the teacher say that 5x3 means 'five lots of 3' where the complainants say that 'times' is commutative (reversible) so the distinction is meaningless as 5x3 and 3x5 are indistinguishable. It's certainly true that not all mathematical operations are commutative. I think we are all comfortable that 5-3 is not the same as 3-5.  However. This not true of multiplication (of numbers). And so if there is to be any distinction, it has to be in the use of English to interpret the 'x' sign. Unfortunately, even here there is no logical way of coming up with a definitive answer. I suspect most primary school teachers would expands 'times' as 'lots of' as mentioned above. So we get 5 x 3 as '5 lots of 3'. Unfortunately that only wor

Why backgammon is a better game than chess

I freely admit that chess, for those who enjoy it, is a wonderful game, but I honestly believe that as a game , backgammon is better (and this isn't just because I'm a lot better at playing backgammon than chess). Having relatively recently written a book on game theory, I have given quite a lot of thought to the nature of games, and from that I'd say that chess has two significant weaknesses compared with backgammon. One is the lack of randomness. Because backgammon includes the roll of the dice, it introduces a random factor into the play. Of course, a game that is totally random provides very little enjoyment. Tossing a coin isn't at all entertaining. But the clever thing about backgammon is that the randomness is contributory without dominating - there is still plenty of room for skill (apart from very flukey dice throws, I can always be beaten by a really good backgammon player), but the introduction of a random factor makes it more life-like, with more of a sense