Players with comparable ability should end up with comparable rank. Reproducible also implies that the meaning of a given score should not change over time. This might be irrelevant for games with an estimated lifetime of a fiscal quarter, but the shelf live multiplayer games extends farther and farther. Our scores also have to be comprehensive. The average player has to instantly and intuitively understand scores.
Scores have to match the player's ideas of significance.
Such performance indicators are also detailed enough. Detail and balance issues are raised by multiple scoring, a common problem for single player, but also for team multiplayer. For frag counting, a kill is a kill is a kill. Yet, human players are not at all identical. Any capable player who chooses to spare the struggling beginners will be beaten by those who target them specifically.