Do 10x Programmers Exist? Says Who?

Certainly, experience is a reasonable way to evaluate ideas, but that doesn't mean the evaluation is valid. I agree that the bloodletting example was meant to undercut the assertion. I also think the assertion - judging only on experience - is incorrect, and that the example is a valid one. We have many examples where experience lead to incorrect conclusions.

By experience, Aristotle argued that things in motion come to rest. Everyone knew that ... until Galileo, further codified by Newton. One's experience can be wrong. Hence the reason for software usability research. See "Making Software", edited by Greg Wilson, for lay results of some of that research. Here's an example of a more direct, empirical study: http://neverworkintheory.org/2011/10/24/an-empirical-compari... .

You write "human beings rely on experience at all times to evaluate." We also use comparison testing, as with that paper link I gave you. A hope is to minimize preconceptions based on one's experience. We see this in the medical field all the time, where we find that even single blind testing can unduly affect the results.

We also use prediction to evaluate. Einstein predicted a certain bending of light around the sun, which wasn't based on experience.

Therefore, I place a weak meaning to "human beings rely on experience at all times to evaluate." We use it to guide our understanding, but also use other techniques besides experience to verify the correctness of our understanding.

If you read my link you'll see that I disagree with Bernhardt's statement. I believe he is guided by Bossavit's work, which argues that there's only been a single test of the 10x principle. Bossavit's essay has two arguments: 1) modalities in the papers show that this is not an established method, and 2) the citations of McConnell all refer to a single study from the early days of software engineering. If you read McConnell's response, you'll see the complaint that Bossavit, by only focusing on McConnell's citations, ignored other studies from the field that McConnell used to draw his conclusion, but which were not in the essay. As I wrote, I object to the modality analysis, as it must surely have a high false positive rate.

But my disagreement is based on research summarizes which have tested the 10x concept, and not strictly on my own experience.

My own observations is that the great majority of practitioners are disdainful of any sort of empirical testing, and will argue that experience always trumps research. I read this exchange as being yet another example of that. I can see why Bernhardt would want to close off the exchange early - it's pointless to have an exchange about research topic X when the other person doesn't even think it needs to be a research topic, doesn't even understand the basic topic, and hasn't bothered to research it.

The correct answer would have been to point to McConnell's rebuttal of Bossavit's statement, at http://www.construx.com/10x_Software_Development/Origins_of_... , as pointed to in that StackOverflow link.

For what it's worth, bloodletting is still in use, though only for a couple of diseases; hemochromatosis and polycythemia being the main two. See for example http://www.ncbi.nlm.nih.gov/pubmed/25175510 . Hence it's not true that "the whole profession has been discredited."