> have been able to successfully track the boost.

lets get nitty gritty on this - can you say how you did this? because a lot of people think this is an unsolved problem

Not the same person, but it really depends on projects. E.g. I have some projects that involve working to large specification sets where we can measure rate of delivery against the spec. If your spec is fuzzy and incomplete, then it gets hard, but then you have little insight into human productivity for those projects either.