A law department I encountered tracks bill write downs by practice groups. The general counsel periodically publicizes the amounts that lawyers in different groups collectively knock off bills from law firms. Lawyers being the competitive types that they are, everyone pays attention to the league table and presumably sharpens their pencils.
Of course, once the general counsel announces that this metric sits atop the pedestal, wily lawyers will figure out how to succeed at the game. One can imagine that some might subtly encourage law firms to bill a bit higher than normal with the expectation that the in-house reviewing lawyer will then shave some off. Also, if a law department institutes some version of this public tournament, the write-offs need to be on a percentage basis, not an absolute basis. Some practice groups barely use outside counsel in comparison to the litigation group.