This is why you can't always trust the plus/minus stat.
Smart's stats:
6 points on 1 for 11 from the field, 0 of 8 behind the arc.
3 assists to 2 turnovers
4 of 6 from the FT line
&
2 steals
Yet he has a +20 for the game?
Or, on the other hand, the problem isn't with the stat, but your assessment about what an effective game is.
The problem is that's can be skewed with low sample sizes. In this case, plus minus is lying like a thief. No sane person can interpret smart's stat line and call it anything less than atrocious.
Unfortunately, you are misinterpreting what plus/minus is all about.
The purpose of Plus/Minus is not to analyse a player's
stats. It's purpose is to analyse a player's
impact.
The entire purpose purpose of plus/minus is to give credit to the guys who impact winning by doing all the little things that don't show up on stat sheets (hockey passes, setting good screens that lead to baskets, playing outstanding defense, boxing out so your teammate can get a rebound, hustling after loose balls, vocal leadership, savvy veteran plays, etc).
The other purpose is to expose the opposite players - those selfish players who are all about individual stat lines, but who hurt the team when they're on the court because they do a lot of negative things that don't show up on the box score (lazy defense, not going after shooters, not boxing out, setting poor screens, stopping ball movement, poor positioning on offense/defense, not executing plays properly, etc).
For example, some players have generated countless turnovers off savvy veteran tricks like 'puling the chair' when defending in the post. This often leads to the offensive player losing their footing and fall over, which in turn usually leads to them travelling, losing the ball out of bounds, or a loose ball that one of your teammates ends up collecting. This not only ends your opponent's possession (and hence, stops them from scoring) but also generates an extra offensive possession (and hence opportunity to score) for your team. That's a potential 4 point swing on a single play, yet it doesn't show up on a stat sheet.
Another example is if you are playing against a great scorer, and you work extremely hard defensively off the ball, so they have to work twice as hard to catch the ball...and when they do it's in a spot where they aren't comfortable. This often leads to any of three possibilities:
(a) The player doesn't touch the ball
(b) The player catches the ball, doesn't see a good opportunity, passes back out
(c) The player catches the ball in a bad spot, can't do what he wants, forces a bad play
Either of the above is a great outcome, and if you are doing this EVERY time down the court, the potential impact that could have on the opposing teams offense is huge - that type of performance could well be the single most important factor in your team winning the game. But if said player has 2 points on 1-6 shooting, 0 assists, 0 rebounds and 1 turnover, then a simply glance at the stat sheet would tell you that the said player had a disgraceful game and did nothing to help the team win.
As with the above examples, if you watch this game it's easy to see some of the areas in which Smart impacted the game in a positive way. His hustle, his ball movement (passes that didn't lead to assists), his defense, his leadership (etc) were all outstanding.
People get too caught up in basic box score numbers, as if a player's individual stats are what determines whether a team wins or loses.
No.
A
team's stats are what determines whether the team wins or loses.
Boston was outscoring the Heat by 20 Points Per 100 Possessions
more when Smart was on the court, compared to when he was off the court, despite the fact that he had a bad shooting night and generally put up unimpressive box score numbers. That tells you all you need to know about his impact on the game (which was overwhelmingly positive).