[thelucky41]

That link has some good references and conclusions based from data. There is a very likely chance that professional programmers can have an impact that is many times that of their colleagues.

The original article is the author's anecdotal evidence that a 10 times difference in productivity is caused by environment. It's enough to generate a hypothesis, at least. After reading a few of the references, I've found it's even harder to generate good data for this than I expected. It would be of no surprise to me that environment is a large confounding factor on what generates these "10x" programmers.