The problem is that there are so many soft factors affecting the outcome that it's very hard to tell if even a great scientific study will apply to your case. The number of people on your team, their experience with the technology being used, their relationships between each other, the politics of the working space and thousands other factors may have much bigger effect on the productivity and quality then the choice of a typing system, and it may be pretty impossible to control for them in the study. I agree that it's good to approach things scientifically, but at the same time it's also good to question how much science applies to the problems being solved.