NRAA Part 3
As of now we have Net Runs Above Average completed in two forms; NRAA in its original form measures raw net runs above average, only within the context of a single season (of course, these totals can be added together to amass career NRAA totals). NRAA2 is used to establish a performance level and make it easier to predict future performance with it. Thanks to James Click of Baseball Prospectus sending me an e-mail with his thoughts on it, I have decided to create a third version of the statistic, pNRAA, or Positional Net Runs Above Average. Since Rate2 is adjusted for position, pNRAA will use PMLV (positional MLV) and work with this formula:
pNRAA = PMLV(100/G) + (Rate2 - 100)
And as always, that figure can be divided by 100 to achieve a per game figure. That number can then be divided by however many number of games you would like to measure to give you pNRAA/n Games.
Mr. Click also helped me with one other thing. He suggested using MLV (total) rather than MLVr (rate), and then multiply that by 100/G to come up with a number. So now the formula for NRAA in its raw form looks like so:
NRAA = MLV(100/G) + (Rate2 - 100)
...rather than the original:
NRAA = (MLVr*100) + (Rate2 - 100)
I'm also motioning for one other change; from now on, NRAA2 will be known as eNRAA, or Established Net Runs Above Average. I like it better.
Let's compare the leaders in pNRAA and NRAA to see how large the difference is. We'll draw conclusions from there.

The list is dominated by some first basemen and outfielders, with a few middle and corner infielders thrown in at spots. Let's see what happens when we use PMLV instead of MLV:

Besides seeing the changes to the top 20, such as Bobby Crosby taking over the second spot out of nowhere, Jhonny Peralta, Marcus Giles, and Jason Varitek also hopping on, there were massive changes to the top 50 (in a spreadsheet on my PC). Jorge Posada, Joe Mauer, Brady Clark, Johnny Damon (notice the trend of centerfielders and catchers) as well as a few more shortstops and second basemen. It looks like pNRAA will have its uses for leveling the playing field entirely, but NRAA is good for use as a raw statistic as well.
Comments, suggestions, criticisms, etc. should be left in the comments section. I think its starting to come along quite nicely now, but knock me down to earth if you have to so I can improve it further.
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I have a couple of questions
2)Do you think pNRAA gives too much credit to positional adjustment, given that the top players in NRAA and pNRAA are totally difference? Or do you think there is general misunderstanding about the importance of defense and positional availablity? I don't really have an opinion myself.
3) Is the average being driven down by a lot of crappy players at the low end of the spectrum? I have this problem sometimes when looking at players.
Nice work.
RE:
- Yes. CF gets more credit than the other outfield positions.
- The purpose of keeping both raw NRAA and pNRAA in existence is for those who feel positional adjustments are too great.
by Marc Normandin on Jul 8, 2005 12:22 PM EDT up reply actions
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The overall stat is a good one. I wish I understood better what it meant. Maybe there should be one place where people can go and read up on a)what the stats in "this" metric mean and b)the thought process behind "this" metric. Basically a cheat sheet, like
"NRAA"
NRAA is a combination of MLV (link), MLVr (link) etc. The formula is "blah". The philosophy behind doing this is "blah".
Having it spread over 3 or 4 posts with refinements in comments and behind the scenes...I just got a bit lost. 8(
The positional stat is a good one, but when comparing positions (SS guys to OF guys) its nearly worthless. All it says is "this guy is as good an outfield as this guy is a shortstop" -- interesting, but IMO not hugely valuable. So the real use of the positional stat should be to compare players within the position, and not much else.
It can tell you about value
Not enough
Possible?
Sure
by Marc Normandin on Jul 9, 2005 8:45 AM EDT up reply actions

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