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The Myth of the Passive Hitter

Posted By Dave Cameron On May 16, 2013 @ 2:41 pm In Daily Graphings | 100 Comments

Apparently, a memo went out to every major media organization that covers Major League Baseball, telling them that they should write about the ever increasing rise of strikeouts in the sport. Back in March, Tyler Kepner wrote this article for the New York Times. Last Thursday, Scott Miller did a piece on the topic for CBS Sports. On Monday, Joe Lemire tackled it at Sports Illustrated. On Tuesday, Anthony Castrovince weighed in at MLB.com. Pretty much all of them hit on the same general points, with a continuing focus being on the change in approach among hitters. Each writer notes that the rise of statistical analysis has taken some of the stigma away from the strikeout, to the point that a hitter who strikes out 150 or 200 times per year is no longer considered to be an offensive black hole.

There’s almost certainly something to that idea, as we even published an article yesterday explaining why the Braves historic strikeout pace hasn’t really hurt their offensive production. It’s hard to argue that the move towards more analytical approaches to team building haven’t decreased the emphasis on strikeouts as a measure of offensive contribution, and it’s likely that the modern front offices care much less about strikeout totals for their hitters than those of the previous generation.

But, there’s another contention in most of these articles that gets tied into that point; that current hitters have adopted a much more passive approach at the plate, and that the rise in strikeouts is due in large part to hitters staring at pitches that hitters 20 years ago would have no problem swinging at. This notion was most obvious in Tom Verducci’s article last month, where he attacked Major League hitters for their passivity.

Welcome to the state of the art in hitting these days, where aggressiveness is disdained and passivity is exalted. The modern hitter is guided by the accepted wisdom in catchphrases such as “driving up pitch counts,” “taking pitches” and “quality at-bats.” There is one serious flaw in this groupthink strategy.

It isn’t working.

Hitters are striking out more than ever before in baseball history while runs, walks, hits and home runs have been on the decline for years. And while teams still preach the religion of driving up pitch counts to “get into the bullpen” of the other team, they may be pushing an outdated agenda.

In that piece, Verducci notes that first pitch swing percentage has declined from 33% in 1988 to 26% in 2013, and that strikeout rate has been climbing steadily the entire time. He even follows the table with the line: “Do the math: hitters are swinging at the first pitch less and less and striking out more and more.”

Well, there’s more “math” to do than simply look at rate of first pitch swings, since strikeouts are a function of all pitches in an at-bat, just not the first pitch. So, since the last few weeks have seen a number of articles talking about just how passive Major League hitters have become, I figured it would be useful to demonstrate the scope of the changes. Thanks to Jeff Zimmerman and Retrosheet, here is the league average swing percentage for 1988 through 2012 (the data for seasons prior to 1988 is incomplete).

Swing

There’s no question that the rate of swings is down since 1988, but look at where the dramatic drop-off really came; the first several years of the sample. Swing% dropped from 46.5% in 1988 to 45.4% by 1991, and has basically hovered around that range ever since. In fact, the 2012 swing% was 45.3%, basically identical to what it was two decades prior. Were the sabermetric devotees pushing Major League hitters to stop swinging so much back in 1990? Because the biggest drop in swing rate happened 10 years before Moneyball was written, not 10 years after.

For a better picture of the changes in how often hitters are swinging, here’s the league average swing rate from 1993 to 2012, so you can see the change just over the last 20 years:

Swing9312

I don’t think you can make a particularly good case that there has been a dramatic change in how often hitters are swinging over the last two decades, and you certainly can’t make a case that it’s a recent trend, as the 45.3% swing rate in 2012 was the highest it has been in MLB since 2005, when hitters swung at 45.5% of the pitches they were thrown.

But, of course, strikeouts are indeed on the rise, so something is going on. If hitters aren’t swinging less often, then there are only two real options left; they’re either taking more called strikes or they’re swinging and missing more often. To show the actual changes on one chart, I made an index of the overall league averages for K%, Called Strike%, Swing%, and Contact% from 1988 to 2012. I then divided the league average numbers for each year by that overall average in order to give us a metric that compares the average in that year to the total average of the last 25 years, where 1.0 is average, and each point above or below 1.0 represents a point above or below the league average over that time frame.

Because league contact rate is 80.5% and league K% is 16.7%, representing them on the same chart masks the differences because the scale has to run from 0 to 100 in order to fit all the data points on the graph. By indexing everything around 1.0, we can easily demonstrate where the changes have been, with each metric compared to its own league average, but placed on the same scale. Anyway, enough words: here’s the chart.

StrikeTrends

Swing rate and contact rate essentially overlap for most of the sample, laying on top of each other right around the average mark. There just hasn’t been a dramatic change in either swing rate or contact rate over the last 25 years. The huge shift has instead come in Called Strike%, and we note that the K% line moves along with the called strike% line in a pretty similar fashion. For those who prefer tables to graphs, here’s Swing+, Called+, Contact+, and K+ for each year since 1988.

Year Swing+ Contact+ Called+ K+
1988 1.03 1.00 0.92 0.88
1989 1.02 1.00 0.92 0.89
1990 1.02 1.00 0.92 0.89
1991 1.00 1.00 0.94 0.91
1992 1.01 1.00 0.95 0.88
1993 1.01 1.01 0.94 0.90
1994 1.00 1.00 0.94 0.95
1995 1.00 1.00 0.95 0.97
1996 1.00 0.99 0.95 0.99
1997 0.99 0.99 0.98 1.02
1998 1.00 0.99 0.98 1.01
1999 0.99 0.99 0.98 0.98
2000 0.98 0.99 0.98 0.99
2001 1.00 0.99 1.02 1.04
2002 1.00 0.99 1.01 1.01
2003 1.00 1.01 1.03 0.98
2004 1.00 1.01 1.03 1.01
2005 1.00 1.01 1.04 0.99
2006 1.00 1.01 1.03 1.01
2007 1.00 1.01 1.04 1.02
2008 1.00 1.01 1.04 1.05
2009 0.98 1.00 1.06 1.08
2010 0.99 1.00 1.08 1.11
2011 1.00 1.00 1.06 1.11
2012 1.00 0.99 1.08 1.19

And this gets me back to the point that I made a month ago. Hitters are swinging at about the same rate as they have for the last 20 years, but they’re taking far more called strikes now than they did then, so the only conclusions one can draw is that pitchers are either throwing a dramatically increased number of strikes overall, or that the called strike zone has simply gotten larger.

Both explanations are possible, and my guess is that the rise in strikeouts is due to a combination of these two factors. We know velocity is trending up, so pitchers may be more willing to pound the strike zone than they used to be. Or we could just have a fantastic crop of talented pitchers who can both throw strikes and get swinging strikes because of the quality of their stuff. However, if the change was primarily due to better pitchers throwing harder, it would seem to have a more dramatic effect on league contact rate, would it not? But that’s not really what the data shows.

And, as I noted in the post linked just above, I think it’s worth noting the years in which the dramatic shift has taken place. While strikeout rate has been going up for a long time, it’s impossible to ignore that it was basically stagnent from 1996 to 2007, but has shot up dramatically since 2008, the first year after the PITCHF/x cameras were installed in Major League ballparks. During the PITCHF/x era, both called strikes and strikeouts have increased at an advancing pace, while swing rate and contact rate have remained unchanged.

It isn’t hard to see how an observer could note the change in the amount of called strikes and link that to passivity from the hitters — after all, if it was called a strike, why didn’t they swing at it? — but the data simply doesn’t support the notion that hitters are taking more pitches than they used to. The data shows that hitters are swinging just as often now as they did 20 years ago, but what the umpire says after they choose not to swing is the thing that has changed the most.

While we might not have historical data on pitches in the strike zone versus out of the strike zone, we do have PITCHF/x data that shows that, at least over the last five years, the rate of pitches in the rulebook strike zone has not increased. In fact, Zone% in 2012 was at its lowest point since the cameras started tracking pitches, and the downward trend has continued through the first six weeks of 2013. And yet, despite the reduced number of pitches in the strike zone, the rate of called strikes has continued to escalate.

Here is essentially what we know: hitters are swinging at and making contact at about the same rates they have for a long time, umpires are calling more strikes, and during the era in which we have the most technology, there do not appear to be an increasing number of pitches actually thrown in the strike zone. That’s what the data shows.

To get from that to “hitters have become passive and are taking too many pitches now” is a leap that the numbers simply don’t support. You could argue that hitters should be swinging more as a response to the rising number of called strikes, because if the strike zone is getting bigger, letting pitchers have free strikes isn’t a great strategy. But, at the same time, the strike zone is the strike zone, and hitters aren’t going to start crushing pitches off the plate regardless of whether it is going to be called a strike or not. If you think watching hitters take a called strike drives down offense, just wait until you see what happens if they start chasing pitches that can only end with a meager ground ball to second base.

If the strike zone has gotten bigger, advocating for a more aggressive approach at the plate isn’t likely to lead to more offense. Offense comes from hitters hitting pitches that they can drive, not making weak contact with pitches on the margins. Telling hitters to swing more often at bad pitches might reduce strikeout rates, but it’s not going to make teams score more runs. So, with all due respect to Mr. Verducci, I think “doing the math” debunks most of his conclusions. It might make sense to explain the rise in strikeouts as a byproduct of the simultaneous rise of baseball analytics, but unless the nerds are forcing the umpires to call more strikes, I don’t think you can blame this on us.


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