This is what +/- and its variants are for. Especially useful for sports like hockey where scoring is rare. Of course, in a work environment this is even harder to try and measure, if for no other reason than that people are almost never 'off the court' and if they are there are many confounding factors.
Yeah, there's a bunch of advanced stats that more accurately model this in sports. My point is twofold:
(a) despite the existence of better stats, a lot of people still care about goals/assists, because they're much easier to understand.
(b) the difficulty of measuring these stats in low-scoring sports (soccer, hockey) is greatly magnified in business; instead of scoring O(1) points per hour, a small software team may "score a point" every couple weeks or quarter or year. Additionally, the number of people contributing is often greater, and we see fewer "identical lineup, but with player A swapped out for player B" situations (and ~never for long enough to get meaningful stats about "points scored").
