H% and Strand

[Raine05]

What is an avg H% for a SP?

I would like to make sure I understand Strand Rate.
So, if a SP w/80+% that should be telling me that he will most likely have his ERA start going up because that SP will be giving up more runs. Correct?

If his strand rate is 65%, or below, his ERA should be better then it actually is and he might be an underrated SP?

Anything between 66-79% is normal, even though a SP might be on the low/high end of normal (say 67%, or 79%)?

How much does RPs effect a SP Strand rate?

Thanks in advance.

[RAY@HQ]

Hit rate should settle to 30%.

Your summary of strand rate is accurate. Factors like quality of bullpen, HR allowed, etc. are what cause the variance in "normal" strand rate. But yes, it's the below 65%/over 80% thresholds that are generally actionable. (Relievers will often sustain higher strand rates because they enter games mid-inning, so only have 1 or 2 outs to get to strand all runners.)

[Raine05]

Thanks again. Just from reading articles from the home page, I see strand and H% are referred to a lot, so I want to make sure I got this.

Can you expand on H% a little. For example, Strand should be between 65-80%, and I know you said H% should be around 30%. But how far off of 30% is a concern to start thinking a Sp is in for an adjustment on his ERA, 5%, 10%, 2%?

Doesn't the team the SP is facing factor in to it (for example, a good ct% team vs a poor ct% team, but then again I guess this evens out over time)?

But doesn't defense and ballpark really play a major role in H%? Almost to the point is it really worth using?

Is there a stat for SP, that includes all contact hits (including ground outs, pop ups, foul outs, etc.)? Wouldn't this really take defense and ballpark out of the equation and show exactly how much a SP actually lets a batter make contact with a ball?

Thanks in advance.

[RAY@HQ]

Hit% will track very close to 30%. There's been a ton of research done on the subject, and there's very little evidence of any "class" of pitcher who can consistently deviate from the 30% level over a large enough sample size. Flyball pitchers will see their h% a touch lower, groundballers a bit higher... but that gets cancelled out by GB guys getting DPs, and FB guys giving up more HR.

You can take a look at the final 2008 stat files, for instance, filter on pitchers with, say, 100+ innings, and sort by h%. You should see the vast majority of those guys with h% between about 28% and 32%. I'd say anything over 3-4% away from the 30% line is "actionable", in that you can pretty safely bet on a correction coming.

As for your other questions:

- ct% doesn't matter, because h% only measures balls in play... no strikeouts or HR.
- defense and ballpark will play a role, but typically a minor one: 1-2%. You can see team-level hit rates in the Weekly Planner team/ballpark report. Even after 3 weeks, you can see how those are settling around 30%. A few more weeks from now, that might give you an idea who the good/bad defensive teams are.

There's much less "noise" in h% than you think. The 30% convergence is not absolute, but it is a very reliable indicator.

[Raine05]

Thanks Ray for the responses.

So, I've been wondering is there a standard rate of how much a SP ERA will be corrected based on abnormal Strand and/or H%? I don't want to use an actual SP (because it is more a general question) but say a pitcher has an 2.00 ERA, strand rate at 85% and H% at .2. Logically his ERA is going to probably go up, but how much up? Will it go up to say MLB avg(right now I think is around 4.5), making his present ERA show him as a very good SP, but in reality he really is just average? Or will it go up higher then MLB avg, hinting to us that he is not really a good SP at all? I guess my question is when based on Strand and H% and someone says a correction should be coming, how big of a correction?

Second question, when a correction to someone ERA is projected, in YOUR experience does it happen very gradually throughout the season say a very bad game here and there, slowly driving it up, or does it seem like a SP might just go on a bad streak of a few games in a row before he evens out? I am not sure if there is any data to answer this question, or it might just be random as to which pitchers we're speaking of.

Thanks and I hope my question makes sense.
Thanks.

[RAY@HQ]

for your first question, it depends on the pitcher's skills, and that's why we have xERA.

Second one, I don't really have an answer.

[Raine05]

But wouldn't xERA also be off because of a low/high H%, since Hits/9 are being multiplied by .575. So, if a SP had .2 h% (his xERA would also be lowered then should be and not truly reflecting what his ERA should be)?

[RAY@HQ]

What xERA formula are you looking at?

xER = xER%*(FB/10) + (1-xS%)*[(0.3*BIP-(FB/10))+BB]

where

xER% = 0.96 - 0.0284*G/F

xS% = 64.5 + (K/9*1.2) - (BB/9*(BB/9+1))/20 + (0.0012*GB%^2 - 0.001*GB% - 2.4)

[Howie M]

Keep in mind that imo it's more likely that a pitcher will consistently UNDERperform via strand rate than overperform.

That is, there can be some pitchers that don't handle pitching with baserunners on very well - nervousness, lack of focus, issue of whether pitching from the stretch, etc.

But I see it as less likely that a pitcher can keep beating the odds, especially if there isn't some wacky factor - bizarre pitch, guy hits the emery board only in a big spot, etc.

Also, while "corrections" usually occur the next year, some pitchers will "get lucky" two years in a row and a few even 3 years in a row. These are the most interesting cases - likely that this is a great pitcher to toss out early in an auction, as he'll probably underperform his bid price. But does he have magic weapon? not likely, but interesting.

[Raine05]

I was looking at xERA (from Gill and Reeves) from Glossary. I guess that formula is outdated and not used anymore but instead xERA2 (Burnson) is currently used. I will take a look at it, thanks.

[Raine05]

Howie thanks for the response....

So in your opinion "corrections" usually occur the following year (or 2 down the line). So, if a SP w/ a very low ERA but also very low H% to date, I should not want to trade away because I think it could just be a matter of time, or be afraid to accept that SP in a trade because he probably could, or might, sustain that h% for the rest of the year?

[Howie M]

I tend not to focus too much on his real ERA in terms of evaluation, but rather on his xERA. And yeah, a guy who looks 'over his head' either by xERA or H% is a possible trade-away target........

[Raine05]

I am having trouble w/xERA formula...please help.

Webb : FB 5
GB 8
LD 2
GB% = .5333
BIP =15
bb 2
k/9 4.5
bb/9 4.5
IP 4

xER% = 0.96 - 0.0284*G/F
= 0.96 - 0.0284*8/5
= .91456

xS% = 64.5 + (K/9*1.2) - (BB/9*(BB/9+1))/20 + (0.0012*GB%^2 - 0.001*GB% - 2.4)

=64.5 + (4.5*1.2) - (4.5*(4.5+1))/20 + (0.0012*.5333^2 - 0.001*.5333 - 2.4)
=64.5 + 5.4 - 1.2375 + -2.40019
= 66.26231

xER = xER%*(FB/10) + (1-xS%)*[(0.3*BIP-(FB/10))+BB]
=.91456*(5/10) + (1-66.26231)*[(0.3*15 - (5/10)) +2]
= .45728 + -391.57386
= -391.11658 should be 5.63

I think I am going wrong somewhere in xS%.

[RAY@HQ]

Raine, I'll just caution you up front that this is a pain in the neck to do yourself. That's why we crunch the numbers for you.

There are some old threads out there where people have walked through the process before, this being one example. You may find some help by copying others' work.

[Raine05]

I understand Ray and trust me I don't plan on doing this for everybody. But what I am trying to do is go through it to try and gain an understanding of what is actually going on and why. Now, it's just bothering me why it isn't working (for me that is). I will check out the link, thanks.