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Old 9th Dec 2011, 19:45
  #59 (permalink)  
Join Date: Apr 2000
Location: gone surfin'
Age: 54
Posts: 2,331
well I guess you can't prove anything. Or for that matter disprove anything. And of course "no evidence of effect," is not the same as "evidence of no effect."

I s'pose there's various ways of supporting the theory that HV vests prevent deaths.

Top of "the scale" in terms of robustness of evidence would be large scale "randomised control trial," designed to prove, "with confidence" that HV vests prevent deaths. The study could involve randomising enough people into two groups, one group wearing HV vests, the other not wearing HV vests. Then follow up death rates between the two.

This probably won't happy for 2 reasons, firstly there's no money in it, and secondly, it's probably not ethical. (Which is why we don't have grade I studies demonstrating the link between smoking and cancer.)

Bottom of the scale is "expert opinion." Known in the research world as Grade V. An example of this would be some high esteemed person, such as myself, moaning that he nearly run someone over on Castle Mill Lane yesterday, 'cos it was dark, and they weren't wearing a HV vest.

Somewhere in the middle are "cohort" or epidemiological study, - eg the airside crew in Lagos wore HV vests, and died less, whilst people got run over by catering trucks at Manchester 'cos they didn't-or were wearing the wrong shade.

I can sniff a research project, anyone up for funding me. Could do with a year sat on me'bum.

Remember having to wear a HV vest for my cross country qualier from EGCB to EGNH. At the time, you didn't have to wear a vest at Barton, but you did at Blackpool. Luckily, I was able to lend one from the legendary Dave D. Only when I arrived back at Barton did I realise it said "Chief Flying Instructor" on the back. Glad no-one asked me any questions
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