I’m linking two sources. Worth going to the sources
https://www.iscoresports.com/basketball/kb/faq_general/what_is_pm.php
Plus/Minus (PM): The PM stat is "Plus/Minus", and reflects how the team did while that player is on the court. If a player has a +5 PM, it means his team outscored the opponent by 5 points while he was on the court. If he has a -3, then the opposing team outscored his team by 3 points while he was on the court.
Efficiency (EFF): (points+rebounds+assists+blocks+steals)-((field_goals_attempted-field_goals_made)+(free_throws_attempted-free_throws_made)+turnovers)
Effective Field Goal % (eFG%): (field_goals_made + 0.5*three_pointers_made) / field_goals_attempted
True Shooting Attempts (TSA): field_goals_attempted + (0.44 * free_throws_attempted)
True Shooting % (TS%): points / (2 * TSA)
Game Score (GmSc): (points + (0.4 * field_goals_made) - (0.7 * field_goals_attempted) - (0.4 * (free_throws_attempted - free_throws_made)) + (0.7 * offensive_rebounds) + (0.3 * defensive_rebounds) + steals + (0.7 * assists) + (0.7 * blocks) - (0.4 * personal_fouls) - turnovers) / games
Here’s another source with more info. In the NBA, being +2.5 means you’re a really good player. Lebron had an 8.9
https://www.basketball-reference.com/about/bpm.html
About Box Plus/Minus (BPM)
by Daniel Myers, creator of Box Plus/Minus
What is Box Plus/Minus?
Box Plus/Minus (BPM) is a box score-based metric for evaluating basketball players' quality and contribution to the team. It is the latest version of a stat previously called Advanced Statistical Plus/Minus; it is NOT a version of Adjusted Plus/Minus, which is a play-by-play regression metric.
BPM relies on a player's box score information and the team's overall performance to estimate a player's performance relative to league average. BPM is a per-100-possession stat, the same scale as Adjusted Plus/Minus: 0.0 is league average, +5 means the player is 5 points better than an average player over 100 possessions (which is about All-NBA level), -2 is replacement level, and -5 is really bad.
Thank you slug. Interesting that this is now on the tech stat sheet but maybe I haven’t paid attention. Just seems a weird stat if as a player you do everything right but the other team out scores or outtalents you and you get a negative rating. So Childress goes 7 of 10 from 3 land doesn’t miss a foul shot only 1 turnover for 28 and has a neg rating. Seems dumb to me. I guess I hope our guys get all positives in the future.