Good points all but I think there might be some misunderstanding….in no place did I say that evidence = studies. I just said that research is one of the primary forms of evidence that should not be discounted as many people seem to do. If the researchers aren’t looking at the exact population, does that make the research worthless? Sometimes but not usually. We should usually still be able to glean information from the studies even if the population is completely different.
Similarly, anecdotal evidence or raw stats (non-research) are other forms of evidence as well that I do not discount at all. I consider the wisdom that Jeremy seems to be discussing as something that can only be acquired through a huge accumulation of personal anecdotal research.
As for the human factor issues I think this is true but it still doesn’t put a hole in the argument IMO….it just shows that sometimes multi-factorial models are more appropriate.