But appeal to authority is the problem. Meta studies are particularly prone to them. While the scientific standard of a good study might be 95% confidence (1 in 20 may be completely rigorous but absolutely wrong), a meta study has no "real" standards.
He eliminated fads...why? He cut his info off at 1950...why?
I would say that as a matter of convenience, he cut off all the hard science biologists that came into being after DNA and genetics became important and biology evolved into hard science.
DK
He tried to cut the fads to get more reliability to his sources. Murray's "Kronbach's alpha[?]"- [quoting from memory, do not have the book at hand right now] coefficients - some statistical measure of reliability - were in the 0.95 range for his meta-studies. On the face of it, 0.95 sounds decent. Besides, his results tend to confirm the general idea of who is hot and who is not, so they are neither revolutionary nor particularly contradictory, but merely provide a measure of quantification. You could get his book ether from Amazon or from public library, it is a pretty decent book.