understanding statistics

[gtrgrl6strng]

Would someone be so kind as to explain the significance of the +/- stat in basketball......

thank you

[tk90]

Hockey has a similar stat. There, it measures goal diffrential when a specific player is on the ice. Like if a player happens to be on the ice when a goal is scored, his rating increases by +1, and vice-versa if he's present when the other team scores.

Whether it's the same in basketball, I'm not entirely sure, but I'd like to think it's similar enough.

Hope this helps!

[petrel]

tk90 is right. Go to the box score for the recent Atlanta Dream game:

www.wnba.com/games/20100619/ATLIND/gameinfo.html

Note that Lehning has a +7 in her +/- column. During the 25 minutes or so when Lehning was on the court, the Dream scored 59 points and the Fever scored 52. We give Lehning the plus/minus of +7 because the Dream was theoretically seven points better than Indiana when she was on the court.

Now, look at Armintie Price's -10. During the 22 minutes that Price was on the court, the Dream scored 45 and the Fever scored 55. (Note: those numbers aren't in the box score, I'm getting them from somewhere else - I just want to show you how the math works.)

So when Lehning was on the court, the team jumped forwards and when Price was on it, it slid backwards. Plus-minus links individual performance to team performance.

It can be misleading because it's very team-dependent. Lehning is a starter, and therefore her plus/minus score benefits as it's very likely that when she's on the court that McCoughtry, Lyttle, Iziane and Erika are on the court. Whereas with Price, it might be that her teammates were C. Miller-K. Miller-Bales-Leuchanka. Even so, sometimes plus/minus gives you some insight.

Bales is the leader for the Dream in season raw plus/minus, by the way, with +52.

[jaye]

pet.... as always... i am in awe of you.....

[bballer]

Agree, that was a good explanation of the +/- stat.

I guess it is supposed to measure some intangible - when a player was on the court the team did well, regardless of whether they had stats such as rebounds or steals, etc. Important to remember was your explanation of who might also be on the court at the same time.

If a player plays for 35 minutes, then the stat is closer to a reflection of the final score.

I wonder if a coach would actually use this statistic? I would think they would rely on their intuitive judgment about the player's contribution. If you looked and saw that several players from the bench (in the game at the same time) had plus ratings it could confirm that the bench did well or held their own.