Umpires Calling Balls and Strikes Better Than Ever Before

The art of calling balls and strikes has long been a topic up for discussion among baseball fans, and if the last century-plus has been any indication, it seems as though professional baseball will have a masked man behind home plate for the prospective future.

But with the advancement of complex technologies such as pitch f/x data, umpires’ jobs have never before come under more scrutiny from the general public. Websites such as ESPN and MLB.com allow fans to visit their websites — for free — and view live game casts in which pitches are tracked and calculated for maximum accuracy and transparency.

Most baseball television broadcasts utilize this, as well, giving an ever bigger segment of the market the ability to say, “What a terrible call! That wasn’t a strike (or ball)! Look at the strike zone box thing!” I’d bet my entire college-student life savings that each of us has said something along these lines at least once.

Yet while the duties of the home plate umpire have never been more transparent in the history of the game, these guys have actually become more efficient at calling balls and strikes in recent years.

League Average Umpire Stats since 2008 (Regular Season)

	Strk%	Zone%	OOZ Clstk%	CC%
2013	63.6	49.4	8.9	88
2012	63.5	48.9	9.5	87.1
2011	63.2	48.6	9.7	86.7
2010	62.8	48.2	10.1	86.4
2009	62.4	48.6	10.5	85.2
2008	62.5	48.6	11.1	84.4

Dating back to 2008, umpires have become progressively less inclined to give called strikes on pitches located out of the zone. In 2008, the league-average ump tagged 11.1% of pitches thrown out of the zone as strikes. Doug Eddings topped all umps in this respect that season, citing a wholesome 14.6% of all out-of-zone offerings as strikes — the highest single-season ‘OOZ’ called strike mark of any ump over the last six years.

The league average OOZ called strike mark dropped more than a half percent in 2009, and with it, the league average ump’s correct call rate (shown by CC% in the table) increased by about the same margin. This perpetuated progressively in the four seasons to follow to the point where the league average home plate umpire accrued a 88% correct call rate last season — highest of any season since our database’s umpire tracking info began in ’08.

These improvements have stretched into the postseason, too. During the 2008 postseason (including the Phillies-Rays World Series), the league average umpire accrued a correct-call rate of 84.6%, juxtaposed to 88.6% last season — mainly due to an out-of-zone called strike rate decrease of 2.1% over that span (11.1% OOZ ClStk% in ’08 versus 9.0% in ’13).

What do these decreasing OOZ called strike rates look like?

Comparing regular-season called strike rate heat maps since 2008

As we can see, the league average umpires’ strike zone has shrunken considerably over the past six seasons. Think that has an effect on a pitcher’s approach? You bet. Due to the lack of calls they’re receiving by umpires, pitchers are focusing in on throwing more ballsin the zone, which is evidenced by an increase in zone rate from 48.6% in 2008 to 49.4% last season and an increasing strike rate (strikes plus balls hit in play) from 62.5% in ’08 to 63.6%.

These increases may seem insignificant, but note that there is a strong correlation between zone rate and in play rate; the more pitches you throw in the zone, the more likely batters are to put those pitches in play.

Which batters and pitchers are most affected by umpires’ shriveling strike zone?

Both righty and lefty hurlers and batters have been affected, but some have been more so than others. Right-handed pitchers have witnessed a 1.5% OOZ called strike rate decrease since 2008 compared to the near identical 1.6% decline for southpaws.

Hitters’ zones have seen more fluctuation in this respect, however. Right-handed batters’ OOZ called strike rate has shrunk 2.0% since ’08 while lefties’ have cut back by 2.4 percent. As for batter-pitcher matchups, it seems that right-handed pitchers and left-handed batters have been most influenced, as umps have called OOZ called strikes 2.5% less since ’08 (2.3% decrease for RHP vs. RHB; 2.1% for LHP vs. LHP;1.4% for LHP vs. RHB).

With this in mind, it seems as though home plate umpires are getting unquestionably better at calling balls and strikes, even in an age where each pitch and subsequent call can be put into question not only in the regular season, but in the postseason, where umpires’ jobs are scrutinized even further. This has directly affected pitchers’ plan of attack against opposing batters, recognizing that stretching the outer and inner corners isn’t working as frequently as it once did.

Expanded replay and challenging rules this season will help the improve the game, especially .

But for balls and strikes?

Instant replay can wait. Umps have never been better.

Comments

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Nice analysis but you make it sound as if more scrutiny would make umpires less accurate in calling strikes.

"...even in an age where each pitch and subsequent call can be put into question ..."

However, the opposite is true, not just for umpires, but for every profession. The more accountable any worker is made to be, the better their performance will be.

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Teddy Danfield

I regularly watch games in addition to pitch f/x on mlb website. Whether data would back it up or not there are an numerous trends of pitches located well within the stated zone that are called balls. Doug Eddings aside, I understand poor catching can lose strikes at times, but there are quite a few non borderline pitches being called balls in recent games.

As a long time fan, I can say that poor umpiring has been and continues to be the worst part of baseball. Playoffs, even World Series have been determined by it. There is a big difference between 1-0 and 0-1. Same with 1-2 and 2-1. Ballplayers have gotten bigger and stronger, while the
umps are still mostly over fifty and out of shape, with deteriorating eyesight etc. Just imagine wearing a mask, while standing behind a burly catcher, watching a 90 + MPH baseball coming toward you. This ball does not come in straight. Depending on the pitch, it may move in almost any direction. Late movement is valued, so while this is happening, you must determine whether the ball crossed the over top of the plate at a height measured from the batters knees to somewhere ( not really known ) above his waist. Not where it was located when the catcher received it ( framing is a joke ).
Now, when I started driving, I had a car with no seat belts, no air bags, no crumple zones, basically a battering ram that you bounced around in or flew out of on impact. Why was this? Because the technologies mentioned, did not exist. Auto deaths are less then half of whet they were back then, even though there is exponentially more traffic on the road.
Baseball needs to figure out what a strike is, measure the players height, and install technology that now exists to bring it into the 21st century.