You could measure this against actual project size (say in 100's of man years). Big companies have, and used to report source LOC instead of binary as a (very approx.) scale of productivity.
There is a quote from Steve Ballmer of all people making fun of IBM for doing exactly that on this thread. And "Any not completely incompetent programmer can double their productivity according to any performance metrics, without any increase in productivity. ", not by Ballmer, but still true.
There are plenty of horror stories of good developers with a brain dead manager, who write excellent code that falls short of the performance metric of the day, and then give up and start writing ****** code that exceeds everyone else's in performance metrics.