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11/09/2007

Comments

Jane Holland

Since I wrote this blog, something has been nagging at me about why the report seemed a bit wrong. Then on Friday evening, I worked out what it was - comparing the performance of these "worst" areas with the national average and not seeing an improvement.

The mean, or in this instance the national average, is affected by changes in all points that contribute to it. Thus if you take say the numbers 1, 2, 3, 4, 5 and 6 and take the average, you get 3.5. If you improve teh lowest number (1) to 2, but keep the biggest teh same, you get a bigger average 3.6, but closer to the lowest number. However if all the numbers increase by 1, the mean is then 4.5, which keeps your lowest improved number the same distance away from the mean. If the best number increases by more than 1, then the mean moves away from the lowest improved number.

There is therefore some flawed logic in the Policy Exchange analysis, in that they needed to look at how much the highly performing areas were improving as well. Are the rich getting richer at a faster rate?

Alternatively, and it would be near impossible to do, you would need a control area that did not benefit from any of the funding regimes - but who would vote or volunteer to be that area?

frank lee

I suppose the other way of raising the average is to lower the top end. How about building sink estates and borstals in St John's Wood and Maida Vale, which lowers the average and thus raises the lowest levels to closer to the average?

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