Right now the game box scores include the +/- stat, which doesn't really show how good a player's defense is, but at least it shows how the team was doing while he was in the game. I think this is as good as it gets since it's really hard to show one-on-one match-ups (i.e. who scored against who) since players are often double-teamed and defenders are often switching assignments even several times on a single possession (zone defense, switches, picks, etc. can cause this). In the end, I don't think we're left with a defensive stat. Even the NBA doesn't have a convenient stat for measuring defensive stats other than the basic number of steals, blocked shots, etc. that we already have. While I understand the desire to see a metric on how well a player played defense, in the end I think we just have to rely on the +/- stat to see comparatively what the impact a player may have had in a game, perhaps factor out his offensive contributions to the +/-, and that may give some sense as how he permed defensively.
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