May 24, 2009

Prospectus Idol Entry

The Importance of Throwing First Pitch Strikes

by Brian Oakchunas

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When MLB.com asked Carlos Zambrano to point to one thing he did during his no-hitter that he'd want to repeat in the postseason, he said, "Strike, first pitch, strike, and challenge the hitters." It is fascinating that Big Z responded this way because he had one of the lowest first pitch strike rates in the major leagues last year along with an uninspiring walk rate. More on what pitchers would like to do versus what they actually do a little later. In the meantime, it is worth looking at how correct his sentiment was and what value the first pitch strike mantra really has.

The first thing we need here is the definition for first pitch strike. The standard use of the term refers to not only pitches that lead to an 0-1 count, but also any balls that were put into play on the first pitch. The idea is that if the pitcher made a pitch that was in the strike zone or made the batter swing, he was throwing a strike regardless of whether it worked out successfully.

Of course, I am not the first person to look at the value of getting it in there on the first pitch. In 2003 Craig Burley found that only 7.3% of first pitch strikes turn into base hits on that pitch. He went on to relate some numbers from at bats that start with a strike as opposed to a ball:

0-0 Strike  .261/.296/.411
0-0 Ball    .280/.385/.459 (ignoring intentional walks)

Looking back at last year, it is informative to view the best and worst pitchers at throwing first pitch strikes (at least 100 IP category):

10 Best                  10 Worst
Mike Mussina    67.6%    Anwrew Miller     51.2% 
Kevin Slowey    67.2%    Barry Zito        51.5%
Ervin Santana   66.7%    R.A. Dickey       51.8%
Cliff Lee       66.6%    Jorge de la Rosa  52.4%    
Greg Maddux     66.5%    Edison Volquez    52.6% 
Dan Haren       66.1%    Oliver Perez      52.9%
John Lackey     65.2%    Seth McClung      53.3%
Javier Vazquez  65.1%    Brian Burres      53.7%
Jorge Campillo  64.3%    Miguel Batista    53.8%
Brandon Webb    64.1%    Greg Smith        54%

In case you were wondering, our friend Carlos Zambrano was a little higher on the bad list at 55%. El Torro aside, one of the first things you notice is that the players in the best column seem much better than players in the worst column. But let's not jump to any small sample conclusions just yet. Think about this: we already knew first pitch strikes were good; it's just that we only had absolute numbers to look at (all first pitch strikes vs. all first pitch balls). When we look at the actual players, we learn that the very best pitcher at throwing strikes, Mike Mussina, was only 16.4% better than the worst, Andrew Miller. As opposed to the 100% difference between Burley's offensive lines that we first looked at, we are only concerned with, in the most extreme circumstances, a 16.4% difference between the worst and best pitchers at throwing first pitch strikes. It bears repeating: those are only the most extreme cases. Most pitchers fall a lot closer to the middle, forming a nice bell curve. In fact most pitchers (using one standard deviation) fall between 56% and 63.4%. While we know that first pitch strikes matter, our question becomes whether throwing them 7.4% more often than someone else really makes that much difference.

In order to answer this question, I compiled (with a nod to fangraphs) data of all pitchers who threw over 100 innings in the last three years. First, I simply split these pitchers into two groups, one group that had a higher than average (average being 59.7%) rate and ones that had a lower rate. I'll refer to the two groups as "strike throwers" and "indifferent throwers". I weighted these pitchers for the number of innings they threw and then found their average rates:

Strike Throwers
62.6% first pitch strikes, 6.62K/9, 2.46 BB/9, 1.04 HR/9 .267 BAA, .305 BABIP, 4.13 ERA.

Indifferent Throwers
56.8% first pitch strikes, 6.30K/9, 3.44 BB/9, 1.06 HR/9 .268 BAA, .302 BABIP, 4.51 ERA. 

Looking at our results, we can easily determine that, yes, throwing first pitch strikes does make some difference or is at least linked to other good rates. Comparing these to Burley's earlier results, it appears that if it has any effect on batting average against or homeruns, it is insignificant when you're only talking about a 5.8% difference between the two groups. Also, while you may have noticed that batters as skilled as David Wright have very low averages after they get behind in an 0-2 count (.218 last year), it is clear that at least after the first pitch, batting average on balls in play is affected very little by the count.

The numbers that do seem to be affected by first pitch strikes are K/9, BB/9, and ERA. These results are very satisfying in a couple of different ways. First, we get what we really want to see, which is that throwing first pitch strikes has a tangible relationship with a good ERA, at almost 0.4 runs of difference between the two groups. Second, we learn why it has an effect on ERA. Pitchers are somewhat more likely to get a punch out and far less likely to give up a walk if they throw first pitch strikes. Furthermore, the effect on ERA is nearly what we would expect to find via the improvement in those two rates.

The stats whizzes out there may be concerned with the nature of this study. That is because I am including all pitchers in the study. The advantage of using all pitchers is that it creates a larger and therefore more reliable sample of players. The disadvantage is that most players fall right in the middle of the bell curve, and therefore, there are a large number of players labeled as either strike throwers or indifferent throwers that actually have a very similar first pitch strike rate.

A way to eliminate this concern is to repeat the study eliminating all pitchers in the middle of the bell curve. In order to do this we can take away pitchers within one standard deviation of the middle. This is just a fancy way of saying we'll take out all pitchers who had a similar percentage between the two groups. To that end, we'll take out all pitchers between 56 and 63.4%. This leaves us with 124 pitcher seasons (as opposed to 419) but it is worth taking a look to see if these results differ. Here, we will refer to the two groups as "extreme strike throwers" and "extremely indifferent":

Extreme Strike Throwers:
65.5% first pitch strikes, 6.85 K/9, 1.97 BB/9, .97 HR/9, .266 BAA, .307 BABIP, 3.81 ERA
Extremely Indifferent:
54% first pitch strikes, 6.26 K/9, 3.90 BB/9, 1.03 HR/9, .268 BAA, .303 BABIP, 4.65 ERA

The homerun rates get a nice little boost here, but it is small enough that it could still just be noise in the study. Otherwise, these results are virtually the same as those in the first study. They merely look larger because there is a bigger gap between the percentage of strikes in the two groups. No matter which way we look at the data, we find the same trends. That said, it helps to illustrate the point that extreme strike guys can be vastly more effective. Any team would love to have one of the 56 pitchers who averaged out to a 3.81 ERA.

Restating the conclusions:

• There is not that much difference in the percentage of times different pitchers throw strikes.
• But even a modest improvement over the league average positively relates to a pitcher's performance.
• Extreme strike throwers tend to be far more effective than their counterparts.
• First pitch strike throwers tend to have better ERAs (approximately .07 runs for every point higher they are in first pitch strike percentage).
• The improvement in ERA is due to a tangible improvement in BB/9 (.17 improvement for each point higher) and K/9 (.05) among first strike pitchers.

Remember Carlos Zambrano's quote? He wanted to throw first pitch strikes; it just never seemed to work out for him. It is easy to get frustrated with pitchers when they can't seem to get their strikes right away, but it's important to remember that it is not necessarily a choice. It is easy to get into a chicken and egg argument where we wonder whether the pitchers are having better walk rates because they throw the first pitch strikes or they have better first pitch numbers because they also happen to have enough control to not walk people. Control superstar Kevin Slowey once said, "Control begets control, and command begets command." When pitchers can manage the strike zone well, they will see the first pitch strikes and the low walk rates and all the good fortune that comes with them. Clearly, both tools relate well with success.