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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IcebreakerXMojican: Field Gulls had a good article on Lynch... Basically says that after six days he'll start losing some of his signing bonus and a few other things, making a total holdout kinda costly.4 min 56 sec ago
PlawsableWhat if the &quot;Thanks for approving spending&quot; quotes were about Castillo and Morales in combination and we&#039;ve only seen the one shoe drop? Castillo comes available at a time when Jones seems to be showing he could be a capable to even very good CF with much more work but isn&#039;t there now. Saunders coming off injury isn&#039;t a good situation to use him there. Ackley hit the same point Jones is at but with a much weaker arm and stopped spending time there. I think Jones has looked better there than Ackley aside from some really bad misplays. There&#039;s Almonte who also still seems to need more seasoning. If you think Castillo can at least be better out of the gate than Jones/Ackley with a glove and bat in CF, there&#039;s a RH regular who requires only cash to acquire. The timing seems perfect.1 hour 20 min ago
rick82We'll see if we dodged a three year headache with Morales. But watching Cruz practically reach the left center warning track last night with a broken bat - that's Smoaking it, gangsta style!2 hours 3 min ago
SABR Mattaaaaaand that's a good reason to gamble on one-year old guys rather than signing 31 y/o players unless they're superstars. :)2 hours 31 min ago
rick82Last two weeks: Swisher: .214/.233/.286 .518 OPS Hart: .261/.370/.348 .718 OPS Season so far, .624 vs. 627 respectively. I had thought Swisher was coming out of it but apparently not. I'm glad we don't have that contract to deal with.2 hours 44 min ago
SABR MattThe Mariners really, truly hate Montero.3 hours 28 min ago
SABR MattWe do, after all, have his countryman Kendrys on the roster...and his fellow Roc Nation Sports client (Cano) is our team leader. Eyes sideways.3 hours 28 min ago
MtGrizzlyMontero will be back in AAA today, Moe. He was evidently packing up after last nights game.3 hours 28 min ago
SABR MattIndeed moj...but sometimes you ahve to take a gamble (see: Abreu, Jose). If I were a scout on this case, I know how much pressure would be on me (I'd probably have a three-month-long migraine preparing for the scouting workout) but I would still, in the end, recommend the Mariners drop $60 mil over 6 years for Castillo.3 hours 30 min ago
mojicianIts advisable to taste the wine before you splurge on a fancy bottle.3 hours 44 min ago
mojicianHow would you like to be a scout with that sort of responsibility? GM: "So your saying Matt, that if I pay Castillo $32 million bucks X 4 he'll turn into Brett Gardner with more power?" These Cuban signings transact $50 million+ based on a few workouts and youtube vids.3 hours 46 min ago
bsrCastillo repped by Roc Nation Sports. I wonder if we built any goodwill over there, with our recent $240M contribution to the cause? :)3 hours 47 min ago
moethedogBTW, in case you missed it: We currently have Morales, Hart, Montero and Morrison on the roster. That's 4 guys who are 1B/DH types. It isn't possible that Hart is going to get RF time, is it? Sigh.....3 hours 50 min ago
SABR Mattthe evidence is in against my earlier consternation with Cuban hitters...the ones with ++tools tend to do well these days. Castillo supposed is bull strong AND extremely fast. A ++defensive corner OF and average CF, line drive hitter...smooth, level swing, no hitches, Brett Gardner style 4 WAR player.4 hours 2 min ago
mojicianLately Cuban sensations have been panning out.4 hours 9 min ago
SABR MattMariners "in on" Rusney Castillo...have serious interest pending the results of his workout for teams. wonder if they have the stomach to bid 6 years though...because he'll likely take that much to get.4 hours 20 min ago
SABR Mattif he holds out he'll be run out of town on a rail. He should definitely not be a moron.4 hours 23 min ago
mojicianAh, a Twelve! So if Lynch does hold out, what is the best course of action for his $ 5.5 million salary? Can the Seahawks sign someone else worthwhile? I am assuming football has something similar to baseball's restricted list and that Lynch would be suspended without pay for refusing to play. Also, if he held out and decided to return, say midseason, would his paycheck be reinstated?4 hours 35 min ago
SilentpadnaIt won't cripple it mo. Christine Michael will help us easily get over Lynch if we have to. (We would have to anyway after '14 for cap reasons). Michael is the best overall athlete in the past two drafts. And Lynch is at that age....I'd rather jettison him a year too early than a year too late....Next Man Up...4 hours 47 min ago
mojicianActually, that's Twelvish to English.5 hours 16 min ago