Monday, 7 July 2014

The smokescreen of stats in medicine, and how to reduce crime

Here is a s
uperb article about the failure of doctors to understand statistics, especially in screening, which leads to completely wrong recommendations. 


Gigerenzer, the clever guy at the centre of this article, suggests a standard set of questions to ask your doctor after he/she has prescribed whatever treatment/screening they urge you to do:
What are the alternatives?
What's the benefit and what's the harm?
Please tell me this in terms of absolute numbers. If 100 take this medication and 100 people don't, what happens after five years?

I am particularly struck by the third question.  I think this would be a lovely thing to apply to education research papers.
If you take the effect our English literacy program ReadingWise English has on 11-year-olds who have reading problems, and increase the term to say, 10 years, the answer is likely to be something like this:
If a struggling 11 year old does our program, he's going to have an average bump of 1 year in reading age.  If his pre-programme reading age was 9, you would expect him to go through secondary school learning very little, go into unskilled employment.  Or be chronically unemployed.  And the chances of the chronically unskilled ending up in prison after 10 years are x per 1000.
Whereas the bump of just one year in reading age would be enough to give him/her the confidence to actually pay attention to his/her secondary schooling, and get at least some vocational training, and therefore his/her chance of ending up in prison would be y per 1000.

So what are x and y?

There is a study by researchers at Northeastern University in the US which used a range of census data to find this out.  They concluded that "about one in every 10 young male high school dropouts is in jail or juvenile detention, compared with one in 35 young male high school graduates.

If we extrapolate these numbers, we would get:
  • If 100 stuggling readers do NOT do ReadingWise English, 10 end up in trouble with the law.
  • If 100 struggling readers DO do ReadingWise English, 3 end up in trouble with the law.
That is a massive difference. 
Yes, yes, you are saying, but that's the USA, not the UK. 
You're right, and I need to research these numbers for the UK, BUT I think it's an entirely predictable that a short sharp boost in literacy for struggling readers in UK secondary schools could make a serious impact on the crime rate.


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