Perpetual Student
Illuminator
- Joined
- Jul 8, 2008
- Messages
- 4,852
It's because one study was observational and the other was from randomized, controlled trials. A drop of 50% is actually weak for observational data. It isn't strong until you see 90% or more. It's easy for selection biases or confounding to lead to differences of 50% or less. Those biases are removed (or at least reduced) in RCT's.
This is the same drop that we saw for hormonal replacement therapy and heart disease or vitamin E and cancer, both of which later were shown in RCT's to have the opposite effect.
Linda
Well. looking at this from the perspective of the science involved, a few questions come to mind. In a situation like this, is it expected that someone will review the procedures and analysis to discover where mistakes were made? I don't buy the arm waving statements that "such is the nature of medical research" or "observational" studies produce errors in the range of 50% to 90%. That is a huge error! In my business (the actuarial field), such errors with a population this big are unheard of. In the areas of science with which I am familiar, researchers would doggedly pursue duplicating or reproducing studies providing false results like this. Was the data manipulated? Were the researchers biased? Was the analysis sloppy? How is it possible to get and error of 50% when a large group like this is studied? Who is responsible? What kind of rubbish science is this? Accepting this kind of thing and simply indulging in arm waving seems to be incompetent and irresponsible! (Not you -- the medical research community)
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