The 10x productivity claim is one of the unfortunate ones, because anyone with a few years of programming experience can relate to the idea, but it's very diffi

The 10x productivity claim is one of the unfortunate ones, because anyone with a few years of programming experience can relate to the idea, but it's very difficult to define an objective hypothesis that can be tested quantitatively in any meaningful way. First you have to define what things like "productivity" are for programmers, and to my knowledge no-one has really done a robust job of even that yet. Then you have to establish who the "best" and "worst" cases are. After all, I suspect many of us would agree that some programmers make a net negative contribution to their projects, taking more time away from more efficient programmers to fix the resulting problems than it would have taken the stronger programmers to do the work themselves in the first place. This may be inevitable, given the learning curve involved in a field as complicated and diverse as programming. That all said, I will just mention that Glass also covers this subject, with various other citations, in "Facts and Fallacies of Software Engineering". Given that his final fact is "Many researchers advocate rather than investigate", a criticism very much along the lines of this article, it would be interesting to know whether his sources stack up to more robust criticism if anyone has access to them.