Measuring "Plate Skills"

One last funky stat: "Hitter's +/-"

Once again, to recap our overall philosophy:  PRODUCTION + PLATE SKILLS + AGE-ARC

We got a new stat to measure "Production," which is called "Plausibility Index," which is covered via the "Allegory of the Window."  I felt there needed to be a stat that incorporated both walks and extra-base hits, but also recognized that strikeouts impact Production by reducing the number of balls in play, and, thereby, increasing the necessary conversion rate (the rate of conversion of balls in play to "random-y singles") to a level that may (if it's very high) make offensive success "implausible."

So what about "Plate Skills," the other part of the formula?

Plate Skills can be measured by on-base percentage, or by "eye ratio" (BB / K), or by separate calculations of K% (K / PA) and BB% (BB / PA).  But, here again, I didn't think we were getting the whole picture.  Just like I view strikeouts as a non-trivial part of Production, I view "hitting the ball with authority" as an integral part of Plate Skills.

In other words, it's not just a matter of distinguishing balls from strikes, it's distinguishing a "hitter's pitch" from a "pitcher's pitch."  The latter two may be balls or strikes, so "just" strike-zone judgment is not enough.  When the hitter gets a "hitter's pitch," what is he supposed to do with it?  Hit it!  So, except as it demonstrates the relative ability to avoid strikeouts (by connecting with the ball), "eye ratio" doesn't really cover that part of Plate Skills.

OBP, then, might be better ... except, (1) it doesn't tell you anything about strikeouts, and (2) it can be  mightily affected by our old friend the "random-y single."  As we've noted, the "random-y single" represents a ball hit without authority, and our system treats "random-y singles" as no better than "random-y ball-in-play outs."  Our theory is that the ability to hit "random-y singles" against minor-league pitching doesn't really tell us anything about a prospects likelihood of major-league success.

So, once again, we devised our own stat, which we dubbed "Hitter's +/-

Without going into excruciating detail (well, maybe we already have), we took what appeared to be a reasonable "average" distribution of our six measurable "plate outcomes" from a bunch of major and minor leagues.  [Again -- going back to the Manifesto -- we weren't looking for a "perfect" model, just something "reasonable."]  [The six are walks, strikeouts, home runs, balls hit with authority (2b + 3b), singles (assumed "random-y" per our assumption), and ball-in-play outs (also assumed "random-y").]

Once we had this "normal distribution" of plate outcomes, there is an "expected" OBP resulting therefrom.  It was .295.  If a hitter's results reflected that "normal distribution," he would have a "Hitters +/-" of 0.00, because he would have neither increased nor decreased his "expected" OBP.

OK (maybe?) ...

We then take each plate appearance and measure the difference between that particular plate outcome and the "expected" OBP.  A strikeout drops that PA's expected OBP from .295 to .000, so each strikeout is weighted at -.295.  A home run or a walk increases the "expected" OBP from .295 to 1.000, so they are weighted at +.705.  Balls in play hit with authority (measured as doubles and triples) we calculated (somewhat arbitrarily) to be worth +.225.

Singles and balls in play hit without authority we assume are neither positive nor negative (but "random-y").  Therefore, they neither increase nor decrease the "expected" OBP.  In other words, they don't count in this equation at all.

So ... for a hitter to achieve a positive "+/-" the value of his weighted XBH + BB must exceed the value of his weighted K.  Singles and ball-in-play outs are assumed out of the equation.  If a hitter achieves that positive value, then he is turning the plate appearance to his advantage vis-a-vis the pitcher. 

That last thing, ultimately, is what we are driving at.  The hitter must "play defense" against the pitcher's attack in order to "play offense" against the other team.  The ability to do that is what this stat is driving at.



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Tacoma Rain's picture

Tacoma Rain

You have not lost me so far... and I do think it makes baseball sense so far from my point of view.


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Gordon GrossWe're gonna strand enough runners to lose this game. *sighs* C'mon man, just one more run for the good guys and none for the bad guys. Memo to the baseball gods: WE are the good guys...37 sec ago
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Bat571If Saunders or Smoak has a near-term replacement, it's Jones, so might as well see what he can do.47 min 11 sec ago
Bat571I want to see James Jones either in the OF or at 1B before they send him down again.50 min 47 sec ago
Gordon GrossOr 5 decent innings from a starter, even.1 hour 16 min ago
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Gordon GrossThat was terrible, Ackley.1 hour 19 min ago
Gordon GrossFINALLY Seager smashes an extra base hit somewhere. C'mon Dustin...1 hour 21 min ago
Gordon GrossWow. Upper deck in Marlins Park. That's some batting-practice stuff right there. Salty DEMOLISHED that. 85 mph, 2-0 count, center of the plate... still think Young is lapping Erasmo and Roenis for a rotation spot, Matt?1 hour 30 min ago
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MtGrizzlyYoung's 85 mph 'fastball' is red meat2 hours 11 min ago
rick82If you begin at exactly two months following his shoulder injury in 2013 ( see, Saunders hit .815 OPS in 244 PAs. The other night against Darvish, he drew a walk and stole a base. He can make things happen. I don't see better alternatives right now. He's also playing strong defense in RF. Put him in RF and leave him there through May. He'll produce at both ends.2 hours 57 min ago
JDDubI've lost hope for Smoak but somehow the flame still burns for Saunders. Probably because his flashes of upside look so good. He's got to be running out of time though.....3 hours 35 min ago
moethedogI may have missed one or two, but by my count, there were 93 guys who played more than 100 OF games last year, 18 (a quick count) had worse OPS's than Saunders. Of those guys, only Josh Reddick, Ichiro, and BJ Upton have ever been widely acclaimed as being fine offensive players. Others: Lorenzo Cain, Brandon Barnes, Chris Young, Eric Young, Justin Ruggiano, Gregor Blanco, Ben Revere, Juan Lagares, JB Schuck, Rajai Davis, David Murphy, Craig Gentry, John Mayberry and Sam Fuld. Eeeeeesh! A bunch of those guys are CF's, as Saunders has been for two years (primarily). I get it, if you're not very good you don't play 100 OF games. I know, I know. But as a RF Saunders is icky gross.3 hours 54 min ago
phxterryMoe - I feel the same way about Seager. I automatically pencil him in as an out, particularly with RISP.4 hours 31 min ago
moethedogHonest to goodness, I cringe whenever I read Saunders' name in the lineup. It is almost stupidly irrational, I know. But even against RHP I just hate to see him in the lineup. Last year, his career year, he was ,249-,338-,414 vR. The league average was .256-.320-.406. In his career year, getting the split advantage, he was a league average bat (and far below it vL). '12 was about the same as he was just below the league vR average. I really don't want to see him in RF anymore. Let us see if Romero can slug a bit or Blash. I am done with Saunders as anything other than our BU CF. Other than that, I don't want to see him anymore. As my daughters would have said 9 or 10 years ago, he's icky gross.4 hours 47 min ago