Archive for Strikeout

I got my start at FanGraphs by writing Community Research articles. As you may have noticed, community authors have been very busy this season, cranking out a lot of interesting articles. One that caught my eye the other day was triple_r’s piece on the importance of strikeouts for hitters. The piece correctly pointed out, as other studies have, that there’s basically no correlation between a hitter’s strikeout rate and his overall offensive production. Strikeouts don’t matter; case closed, right? Well, not exactly.

Let me present a hypothetical situation. Say there’s a group of players who go to an “anti-aging” clinic in Florida and pick up some anabolic steroids. Let’s say these hypothetical players are named Bryan Raun, Ralex Odriguez, Tiguel Mejada, Phonny Jeralta, Celson Nruz, and Barry Bon… nevermind. Yet, after using the steroids, it appears that the group of them, on average, has not improved. The steroids didn’t improve their performance, right? But, wait — let’s also say that while visiting Florida, some of them contracted syphilis, which spread to their brains, causing delusions and severely impacting their judgment, strike-zone and otherwise. The players whose brains aren’t syphilis-addled have actually improved quite a bit, but their gains are completely offset by the losses suffered by those whose central nervous systems are raging with syphilis. So, the fact that the steroids actually do improve performance has been completely obscured by another factor that is somewhat — but not necessarily — associated with the steroids.

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“Riddle me this,” wrote editor Dave Cameron to me some time ago, “what happens when an unstoppable force meets an immovable object?”  OK, that’s not exactly how it went down.  What he actually did was to present me with the challenge of research, with the goal being to develop a model that would forecast the expected odds of an outcome of each match-up between a specific batter and a specific pitcher. Rather than talking about how players have done in small samples, can we use our understanding of player skillsets to develop an expected outcome matrix for each at-bat?

For example, such a tool might tell you that Adam Dunn has a 40% chance of striking out against Stephen Strasburg, a 10% chance of drawing a walk, a 5% chance of hitting a ground ball, etc… Forget I said those particular numbers — I completely made them up in my head just now.  You may be thinking “well, why should I care about that?  Rather than just being inundated with match-up data that is little more than randomness, such a tool might give you some idea of how much of a gain in expected strikeout rate a team would get by switching relief pitchers with a man on third base and less than two out. Or what the probability of getting a ground ball is in a double play situation, which might influence the decision of whether or not to bunt. Knowing the odds of potential outcomes could be quite beneficial in understanding the risks and rewards of various in-game decisions.

This project has been — and will continue to be — a major undertaking, as you can imagine.  This isn’t the kind of thing that can just be thrown together, but I really think the results could be great. Today, I’ll be sharing with you the findings of my research into perhaps the most important aspect of these matchups — K%, or strikeouts per plate appearance.  This will introduce the sort of process that will be involved in figuring out all of the other elements of the matchup tool. Read the rest of this entry »

So long as you didn’t bring the party too hard over the Christmas holiday, there’s a chance you remember the article I submitted for the readership’s consideration last week. In said article, I roundly praised research conducted by Lookout Landing’s Jeff Sullivan this past August — research in which he explored the relationship between pitcher contact rates and strikeouts. Moreover, I posted a Top 10 Leaderboard of the starting pitchers (50 IP and up) with the best Contact%.

Well, in the comments section of said article, user Toffer Peak brought to our collective attention a study done by user matthan over at DRaysBay. Matthan is the user name of Matt Hanna, and his work is an exciting complement to Sullivan’s as it gives us some idea of the importance of Out-of-Zone Swinging Strikes (OZSwStr%) relative to In-Zone Swinging Strikes (InZSwStr%).

The relevant article provides all the answers your little heart would desire — complete with a Google spreadsheet of every pitcher from last year — but the relevant content for our purposes is this formula that Hanna concludes is the best fit for calculating Expected Strikeout Percentage (eK%). Said formula goes:

eK%=(ClStr%*.9)+(Foul%*.5)+(InPly%*-.9)+(InZSwStr%*1.1)+(OZSwStr%*1.5)

The Adjusted R-Squared is: 91.4%

The surprising result here is the degree to which OZSwStr% is weighted over and above InZSwStr%. Nor does that even account for the fact that the average for OZSwStr% (4.89%) is already about twice as a high as InZSwStr% (2.73%).

Once we adjust for that difference as well, OZSwStr% comes out to roughly 2.5 times more important than InZSwStr%. If I’m being honest, I’ll say right now that that runs counter to what I would’ve guessed. My impression has always been, if a pitcher can throw a pitch past a swinging batter but still place said pitch within the strike zone, then he (i.e. the pitcher) would be truly unhittable. What Hanna’s research suggests is quite the opposite, in fact: A pitcher who is able to induce swings (and misses) at pitches out of the zone is, in fact, most likely to tally big strikeout numbers.

This research is quite relevant to the present interweb site, as FanGraphs carries both O-Contact% and Z-Contact% on every player page and in the leaderboards section.

And though, much like Forrest Gump, I’m not a smart man, I thought it might make sense to create a leaderboard in which O-Contact% (or OZSwStr%) was given its due. To that end, what follows is a Top 10 list of the starting pitchers with 50+ IP who led the league in what I’ll call Adjusted K. In fact, what I did was to find how many standard deviations all such pitchers were from the mean in both O-Contact% and Z-Contact%. I then multiplied the O-Contact% standard deviation by 2.44 and averaged it with the Z-Contact% standard deviation. Here are the results (SDO = Standard Deviations from O-Contact% mean / SDZ = Standard Deviations from Z-Contact% mean):

This list greatly resembles the one we looked at last week — with one exception, that is: Freddy Bloody Garcia. Granted, he only pitched 56 IP through nine starts last year, but it appears to be a skill he’s carried throughout his career, as his 46.5% lifetime mark suggests.

So that’s one thing. Now here’s another question of some interest, I think: Which pitchers posted the biggest O-Contact%/Z-Contact% splits in 2009? In other words, which pitchers are best at getting swinging strikes outside the strike zone despite allowing somewhat frequent contact within it. Truly, this would be a list of pitchers who use their talents most efficiently, getting swings and misses outside of the zone, where they are more valuable. Here’s a list of such pitchers (SD O-Z = Standard Deviation of O-Contact% minus the standard deviation of Z-Contact%):

Some of those guys are what you might describe as a pretty big deal. Carpenter and Wainwright, certainly, were at least part of the Cy Young convo in the National League — and both accomplished the feat while conceding a below-average contact rate on balls in the strike zone.

There are certainly other questions to ask about this work. I’m in Paris right now, though, so I’m probably not gonna ask them for at least a couple days.

Though it’s quite brief, I have to believe that Jeff Sullivan’s post on the correlation between pitcher contact rates and strikeouts from this past August has got to be one of the most exciting of the year. It makes so much sense — miss bats, get strikeouts — and yet Mr. Sullivan appears to be the only one on the interweb (besides our own Matthew Carruth) asking substantive questions about it*.

*If there are others, please don’t hesitate to mention them below.

You can see the correlation between the two in this image I’ve stolen directly, unforgivably from Lookout Landing:

That’s pretty striking. And it begs a question: If the correlation between Contact% and pitcher strikeouts is so strong, then couldn’t Contact% help us understand which pitchers might be poised to top the strikeout charts next year?

Yes. With some caveats.

In that same post to which I’ve linked above, Sullivan also notes that, beyond Contact% (league average 80.5%), pitchers also control their strikeout rates by other means, such as First-Pitch Strike% (league average 58.2%), Zone% (league average 49.3%), Called Strike%, etc. While none of these factors correlate as strongly as Contact% to pitcher strikeout rates, it does appear as though they’re not entirely negligible, either. To that end, I’ve included the first two of those below for comparison’s sake.

What happens when we run the 2009 numbers for Expected K%s (xK%)? That’s the question I asked myself — and which I answered, I think, by means of the kinda dumpy looking table you see below. Here are the Top 10 starting pitchers (50+ IP) by Contact% with expected and actual strikeout rates, plus K/9:

So, what do we see here? Some likely suspects, for sure: Harden, Lincecum, Vazquez, de la Rosa. But also some surprises: Felipe Paulino (second!), Gio Gonzalez (third!), and Bud Norris. The first two of those guys I wrote about last week as tRA* surprises. Bud Norris I didn’t mention, but he actually finished 66th in tRA* out of the 183 pitchers with 150+ xOuts.

What conclusions can we draw from this? Well, we should probably be careful about that, as more research needs to be done in this area. Still, it’s probably reasonable — given his xK% and overall profile — to expect at least a small improvement in strikeouts from Felipe Paulino. Moreover, there’s reason to think — given his excellent Zone% — to think that Bud Norris will probably turn some of his walks into strikeouts.

How well do you think Norris will perform in 2010? Enter your Fan Projection here.