Quote:
Originally Posted by NoahSD
The second half of the study is indeed inappropriate and meaningless. I explained exactly why. Appeals to authority don't really mean much when I'm not saying "I heard that that study sucks" but rather "Here is exactly why this study sucks." Again, they used the same set of subjects for the five-year as the one-year, which is completely inappropriate and makes the study worthless. One quarter of their subjects quit (from memory since I gotta run in a sec), which also makes their results worthless.
I wish we could get an independent expert in longitudinal research methodology to comment on this particular study. As it stands, you and I would probably continue to go back and forth, and since I started this sidebar, it probably isn't contributing much to the overall thread. I'd rather move on to other points to discuss/debate.
The methods they employed are no different than deciding at the outset: we're taking these two groups, experimental and control, and following them for 5 years. We'll take a baseline measure, then one at 1-year, and then a final 5-year follow-up with both groups. Results at each time interval will be published. Very standard and appropriate methods. The difference in this case, it appears, is that the researchers did not originally plan to do the 5-year follow-up, but made that decision at the 1-year point. IMO, this difference does not bias the overall study. Availability of funding and staff, willingness of participants to continue with the study, and statistical power of the sample size would all factor in to how they make these determinations. But these factors are largely separate from valid research methodology.
The drop-out rate in the study is not primarily the fault of the researchers, nor should it be held against them, aside from the small sample size at its end. The results aren't using the measurements from the drop-outs, so I don't see why this is a major point for you. Not ideal, yes, but worthless?
Again, I don't hold these folks as gold standard, nor do I view veganism that way, but you don't appear willing in the slightest to consider that there may be kernels of helpful information, from a general health perspective, that may be derived and applied from primarily plant-based human diets. I do appreciate your opposing viewpoint, which gives me a starting point to dig deeper.
Last edited by Tablerat; 09-18-2011 at 09:58 PM.
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