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Positional PER

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Post#21 Re: Positional PER
Sun Jan 13, 2013 5:03 pm by Doctor MJ

turk3d wrote:Swap teams and you might see a totally different result. That's why I like the idea of looking at who wins the head-to-head matchup. It tells me a lot more about a player than some of these advanced stats being used. Do you outscore your man or does he outscore you the majority of the time?

Ben Wallace is the exception here. He constantly beat his man in rebounding and he was a great help defender (Positional metric doesn't take this into account) but it still says a lot.

In Wallace case, I want to know what his +/- was when he led the league in rebounding (2001, 2002 and even 2000 when he averaged 13.2) . And I'm not interested in his per 48 that much (he didn't play for 10 or more mpg on average). You seem to be factoring in someone else play at the position and I'd like to see what their +/- was.


mystic's already saying some spot on stuff here but this jumped out to me.

There's an expression, "The exception that proves the rule", and it means basically someone or something so outstanding that by including the caveat it gives the rule even more gravity. "Dude, you are not Steve Nash, when you jump up in the air and then try to find a guy to pass it to, you will just end up wasting the possession just like the rest of us 99.999%."

To me you're clearly implying that Wallace is one of those type of outlier exceptions, and it sounds good because the dude IS an outlier in a lot of ways. Wallace however did not get a free pass from the normal rules because everyone recognized he was an outlier talent. He earned playing time because it's really not at all unheard of for one or even two of your five guys on the court to have scoring as an extremely low priority.

Joel Anthony for example did not start on the Miami championship team because he was an outlier talent. He started because of what the team needed in order to balance them out given their other talent. Now, Miami certainly was an unusual team - obviously Anthony doesn't get the start on most teams - but the key takeaway is that coach simply are not looking at designing their 5-man-lineups based on individuals who can outscore their opposing man and therefore if you are doing your analysis as if that were the goal, you simply have to expect that your approach is going to go wrong at times.

Now you can certainly say "Hey, I'm just talking about a first pass algorithm. Of course I go deeper than that.", and that's fine. However in a thread where we're basically talking about tweaking an existing an advanced stat to INCLUDE the bias, alarms are being set off. If a bias needs to be added into the mix in order to do the desired first pass analysis, it cries out to ask whether you need to be a little more flexible even in your first pass approach.
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Post#22 Re: Positional PER
Sun Jan 13, 2013 6:03 pm by turk3d

turk3d wrote:Swap teams and you might see a totally different result. That's why I like the idea of looking at who wins the head-to-head matchup. It tells me a lot more about a player than some of these advanced stats being used. Do you outscore your man or does he outscore you the majority of the time?

Ben Wallace is the exception here. He constantly beat his man in rebounding and he was a great help defender (Positional metric doesn't take this into account) but it still says a lot.

In Wallace case, I want to know what his +/- was when he led the league in rebounding (2001, 2002 and even 2000 when he averaged 13.2) . And I'm not interested in his per 48 that much (he didn't play for 10 or more mpg on average). You seem to be factoring in someone else play at the position and I'd like to see what their +/- was.


Doctor MJ wrote:mystic's already saying some spot on stuff here but this jumped out to me.

There's an expression, "The exception that proves the rule", and it means basically someone or something so outstanding that by including the caveat it gives the rule even more gravity. "Dude, you are not Steve Nash, when you jump up in the air and then try to find a guy to pass it to, you will just end up wasting the possession just like the rest of us 99.999%."


Doctor MJ wrote:To me you're clearly implying that Wallace is one of those type of outlier exceptions, and it sounds good because the dude IS an outlier in a lot of ways. Wallace however did not get a free pass from the normal rules because everyone recognized he was an outlier talent. He earned playing time because it's really not at all unheard of for one or even two of your five guys on the court to have scoring as an extremely low priority.


Doctor MJ wrote:Joel Anthony for example did not start on the Miami championship team because he was an outlier talent. He started because of what the team needed in order to balance them out given their other talent. Now, Miami certainly was an unusual team - obviously Anthony doesn't get the start on most teams - but the key takeaway is that coach simply are not looking at designing their 5-man-lineups based on individuals who can outscore their opposing man and therefore if you are doing your analysis as if that were the goal, you simply have to expect that your approach is going to go wrong at times.

The reason that Joel Anthony starts is because Miami does not have the ability (trade chips they would trade) or cap space to go out and sign a FA who's better. AMOF, I don't think he does start any more (they've move Bosh into the starting Center position and if the had someone better they'd move Bosh back to PF where he prefers to play.

One important factor in all this and I'm not talking from a fans standpoint (a lot of these fancy analytics might be appealing to them) is that you have coaches (GMs probably have more interested in some of the advanced stuff) who use mostly their knowledge of the game and experience which weigh a huge part in their decision making. In addition, a coach might want to see how stacks up position wise as he may be constantly molding his team (sometimes the styles you play is based on the players you're stuck with).

Nellie when coaching the Warriors his 2nd time around, did this playing Al Harrington as his primary Center for several years and playing his SFs @ PF. Nellie's the extreme case (outlier you might say here) but nonetheless is a case. Yes, the game is based on many facets, but I believe points scored vs points given up (net points) is perhaps the least common denominator in figuring out wins vs losses.

If I'm a horrible defensive player, but outscore you 32-30 (and if giving up 30 is my average) I've basically won my matchup. As for the intangibles, that's something the coach should see if he's doing his job and if he notices that others are getting beat due to your defensive ineptitude, then he can make the appropriate adjustment.

Doctor MJ wrote:Now you can certainly say "Hey, I'm just talking about a first pass algorithm. Of course I go deeper than that.", and that's fine. However in a thread where we're basically talking about tweaking an existing an advanced stat to INCLUDE the bias, alarms are being set off. If a bias needs to be added into the mix in order to do the desired first pass analysis, it cries out to ask whether you need to be a little more flexible even in your first pass approach.

And basically, I'm just making a suggestion here, not saying that it's a great idea one way or the other, it's just something that I've been thinking about a little lately and the OP sort of seemed to relate to this idea. You really don't need per, just points scored vs points given up. You can use the other already existing metrics to determine other facets such as defense (RAPM for example), rebounding etc. I think that the first pass (what positions you are winning at and which ones your losing) has value in that it then can tell you which ones you need to go in further depth on, to see which are the players who are constantly getting beat.

As for guys like Ben Wallace, the coach (probably without stats other than maybe rebounding and blocked shots) can tell how valuable he is to the team. Again, here you might possibly see the Anthony syndrome here, who do you have 2nd in line? John Salley? I think it's pretty obvious who's going to be more productive for you.

I'm flexible, just think this is breaking things down to their most simplistic approach and no need to repeat something that's already being done in another metric. Not trying to replace anything, just perhaps add something that I feel could prove useful to some people. Whenever developing a methodology it can typically be done in stages. Makes it simpler that way.
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Post#23 Re: Positional PER
Tue Jan 15, 2013 12:18 am by penbeast0

One more thing. Teams may only move guys over 1 position for defensive purposes but still, there are a lot of Devin Harris/Chauncey Billups type SGs right now in the league to go along with all the traditional SF/SG type swingmen. So, you can't say, gee . . . why don't we penalize PGs and give a bonus to SGs (or penalize SFs and give a bonus to SGs as the case may be) without accounting for all these two.

Most players in the NBA except for the smallest PGs and slowest Cs are basically 2 position players defensively which is where matchups matter. Some can guard 3 positions but generally you can consider most players defensively as either combo guards, swingmen, combo forwards, or post defenders. And, if you rate them that way, I would guess without looking that a lot of the PER differentials drop out although there is still probably a bias against off ball players like a lot of wings and in favor of bigger players who play closer to the basket due to rebounding.
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