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Thursday, 25 October 2012


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I believe there are some 700,000 children in state care homes. The outcomes for these children are terrible, three quarters of them end up as criminals or drug addicts or both. Wouldn't it be nice if the government concentrated on these children instead of harassing people who are managing quite well without their attention? Perhaps we could make Mr Clegg Minister for Children in Care, with his pay linked to his success rate.

I've posted this comment at AnnaRaccoon.

About Duncroft: here's some arithmetic based partly on guesses at numbers I don't know. Corrections by anyone who does know the numbers welcome.

You say that all the girls had an IQ of over 140. Assuming a mean IQ for the population of 100, and a standard deviation (SD) of something a little less than 15 (because back then people were less given to standardising SD at 15), and allowing for the fact that the female SD was usually measured as being slightly lower than the male SD, the girls have an IQ roughly 3 SDs above the mean i.e. in the top 0.0013 fraction of the female population. The population of England and Wales was (somewhat below?) 50 million, and life expectancy was (somewhat below?) 80 years, so - ignoring the "baby boom" phenomenon - the number of 16 year-olds must have been about 625000, of which something like 310000 would be girls. So the number of 16 year old girls with an IQ of over 140 in E & W would be only 0.0013 x 310000 = about 400.

How many of these would be in ‘need of care and protection’? Recall that, contrary to popular prejudice, high IQ people are typically healthier, physically and mentally, than the general population. Assume that girls are less likely to be sufficiently troubled souls to be potentially in ‘need of care and protection’ than boys. I'm going to guess that it would be less, perhaps much less, than 1 in 40. So now we are down to 10 girls aged 16. Recall that high IQ girls are proportionately more likely than the general population to be middle class rather than working class; so how many of these troubled souls would be given up by their families to such institutions? Perhaps a quarter? We're down to 2.5 girls. Assume that these girls are split evenly between just Duncroft for the South and one other institution covering the North and Midlands. That leaves 1.25 aged 16 at Duncroft i.e. roughly just you, Ms Raccoon.

It's not clear that your story adds up.

"some arithmetic based partly on guesses at numbers I don't know"

Not an auspicious beginning, DM, and most unlike you. Not that I'm arguing, mind, I don't 'do' sums and anyway my suspicions concerning the usefulness and/or veracity of 'intelligence tests' even exceeds my suspicions of the late Sir James!

Almost all social arithmetic is based partly on guesses: the question is whether the writer confesses that he has made guesses. Not being a Social Scientist, I do. It is therefore about the most auspicious beginning you can devise.

The usefulness of IQ tests is irrelevant to the point. Read it and see.

"So the number of 16 year old girls with an IQ of over 140 in E & W would be only 0.0013 x 310000 = about 400."

Rank male chauvinism and I feel it my duty to report you to 'Harry Harperson' instantly!

I watched some of the BBC coverage, and realised that I had once known one of the star witnesses claiming to have been abused. Only a quick chat or two, but colleagues of mine knew them rather better. I have to say that they are not my idea of a reliable or particularly well-balanced person. Maybe the Savile experiences made them that way? Who knows...

The only one who really knows the lot is dead and can no longer 'fix it'!

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