I disagree on SLOC being a bad metric. It may be moot to go into a years-old question with eleven answers, but I'll still add another.
Most arguments call it a bad metric because it is not suited to directly measure productivity. That is a strange argument; it assumes the metric to be used in an insane way. With this reasoning, one could call the Kelvin a bad unit because it is unsuited to measure distance.
Code length is a viable measure of ballast.
The amount of non-comment code lines correlates with:
- undetected errors
- maintenance costs
- training time for new contributors
- migration costs
- new feature costs
and many more similar kinds of costs, like the cost of optimization.
Of course SLOC count isn't a precise measure of any of these. Code can be anywhere between very nice and very ugly to manage. But it can be assumed that code length is rarely free, and thus, longer code is often harder to manage.
If I were managing a team of programmers, I would very much want to keep track of the ballast it creates or removes.