mischievous wrote:Dr Spaceman wrote:It's the best stat currently in existence.
Some people will scoff at this, but just think on this: what are we actually trying to evaluate when we look at a basketball player? Answer: How well does he help his team win? (Can be restated as: what effect does he have on the scoring margin?) The reason I hold RAPM in such high regard is because it is literally the only stat that actually attempts to answer this question. Any box score stat you can think of doesn't even try. Quite literally, RAPM is the only stat that has any validity for what people are actually looking for in a stat, even if they don't quite realize it.
There's nothing inherently wrong with using the box score, as long as you realize that it is, at best, a proxy for what you actually want to know. There can be great players who score 20+ ppg, and terrible ones who do the same. But there will never ever, by definition, be a terrible player who makes a hugely positive impact on his team.
Once I came to realize this, I became a big RAPM convert, and I live with the flaws because it's the only thing that can actually tell me what I want to know. It might miss the mark by more than the box score will, but at least the mark in this case is clear, and it's exactly what I want it to be.
So really this is the whole reliability vs. validity issue. People dislike RAPM generally because it challenges what they thought they knew. The fallacy is in thinking that you ever knew anything by looking at the box score anyway. So yeah, in small samples we have some results that are absolutely nuts. Granted. But with big samples, and enough noise correction, we zero in on exactly what we really want to know. That's beautiful, and it's something no other stat in existence can accomplish in the slightest.
Now I'll add the caveat that RAPM never thinks for me. I would never use it to rank players, or the crux of an argument, or anything of the sort. But as you guys know, I watch a ton of film, and generally find that what I see lines up with what plus/minus data shows. Obviously Manu Ginobili isn't the best player in the league, but when he comes in the Spurs play really well, and that's what RAPM tells us. Now Kevin Durant has a lower RAPM, but a much huger role and more minutes, so quite obviously he's the better player. I think sometimes people who use RAPM get pisgeonholed into using it as the be-all-end-all, and that's not what I do at all.
Final thing: RAPM is at a crossroads right now, and it's either going to head into RPM (wrong direction) or PTPM (right direction). This has everything to do with how I feel about the box score.
Basically what you're saying in all of this is, "RAPM is better than all other measures because i said so, and anyone who doesn't use RAPM is wrong or ignorant."
Dr. Spaceman never said anything like it. He told us why he likes the stat and how he uses it. That's his opinion.
If you dislike the stat, then tell us why but don't reply like that. It adds nothing to the discussion and it's desrespectful.
I personally don't use it, but that doesn't mean I can't understand someone who does.
