hard-hit and other %

[hitbypitchratio]

Hi Todd,
I asked you about hard-hit rate on Twitter earlier and when it stabilized. You said it's backwards-looking, and not predictive. So that leads me to ask what good is it then? Is it not used to point to a skills change/decline? Are swing and contact useful only because they speak to a change in approach and its sustainability?

[Todd Zola]

We're all still learning about the predictive capability of the data. We're really good at reverse-engineering what happened, not so good at applying that to the future. Some of it is a leap of faith -- so and so worked with a swing coach and is getting results. The problem with that is we only hear about the success stories.

From Fangraphs:

“Stabilization” Points for Offense Statistics:

60 PA: Strikeout rate
120 PA: Walk rate
240 PA: HBP rate
290 PA: Single rate
1610 PA: XBH rate
170 PA: HR rate
910 AB: AVG
460 PA: OBP
320 AB: SLG
160 AB: ISO
80 BIP: GB rate
80 BIP: FB rate
600 BIP: LD rate
50 FBs: HR per FB
820 BIP: BABIP
“Stabilization” Points for Pitching Statistics:

70 BF: Strikeout rate
170 BF: Walk rate
640 BF: HBP rate
670 BF: Single rate
1450 BF: XBH rate
1320 BF: HR rate
630 BF: AVG
540 BF: OBP
550 AB: SLG
630 AB: ISO
70 BIP: GB rate
70 BIP: FB rate
650 BIP: LD rate
400 FB: HR per FB
2000 BIP: BABIP

This is the number of events necessary to have each sample be 50 percent real. It doesn't mean that level will be the same in the next "X" events.

I still use it as a measure of predictability, by regressing towards the year-to-date skill - just not as quickly as implied by these stabilization points. The degree does match the above, I just don't regress according to these number of events. I'll explain my process soon, likely in a Rotowire piece, also available for Platinum subscribers.

[hitbypitchratio]

Thanks for such a detailed reply. I'll be highly interested in that piece for sure. Are there stabilization points established yet for hard-hit rate? You'll recall I was worried about Jay Bruce...I know you said all bets are out the window if he's hurt, but supposing he wasn't, would a 19% hard-hit rate, barely half his career average, worry you at this point in the season?

[Todd Zola]

There isn't any reliable data point on any of this stuff. It's all backwards looking.

This has been a goofy season -- cold weather, postponed games, etc. Teams are playing the same teams twice, facing better or worse rotations in a cluster. Bruce started OK, he's now in a slump. It's baseball.

Maybe check this out...

https://www.fangraphs.com/library/offen ... act-stats/

[hitbypitchratio]

Yeah, I guess that could just be Bruce's general streakiness too. Thanks!