Since the best you can show with this is a loose correlation, you're going to run into troubles across different fields. For example, the Intelligent Design people aren't rigorous in their methodologies and don't produce a lot of academic writing. So they don't fit your model. Maybe if you add all non-academic sources, like the propaganda they produce?
Also, if you add in some of the hyper-productive people, like Bach and maybe Noam Chomsky, I think that would skew the results even more. How do you evaluate Bach? He was clearly productive - or does this not count b/c it's in music?