Have steroids in baseball really affected statistics? (7/9/12)

Yes. Yes, they have. But that’s just part of the story.

The numbers, when compared with a timeline of important events in the “steroid era” of Major League Baseball, seem to show that the use of steroids have increased offensive production. Any baseball fan knows that the amazing 1998 home run season may have been tainted by steroids and other performance enhancing drugs. But, that season was no where near the peak of home runs produced in the last 20 years. That was just the beginning. How has steroids in baseball really affected the game?

Many have seen the statistics for home runs during these seasons, but what about other statistics like strike outs and walks? How do they compare from year-to-year?

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A quick look at these charts and one could possibly come to the conclusion that the inflated stats are the direct result of steroid use. Let’s keep in mind that it was not just All-Stars like Mark McGwire and A-Rod who were using PEDs, guys who were barely on the team also added to the total home run tallies — possibly due to steroid use.

But, it gets a little bit more confusing when one looks at the statistics for strike outs and walks throughout the past 20 years. The early and mid-1990s were filled with seasons that had sub-30,000 strike out years. There hasn’t been one of those since 1997. Strike outs stayed steady throughout the “steroid era” of the early-2000s and then have increased year-after-year beginning in 2005. The past four seasons have seen the most strike outs of any season in the history of professional baseball — and 2012 looks like to also be a record year as there have already been 19,084 by the All-Star break.

Strike outs have certainly gone up since the “steroid era,” but oddly enough walks have not. In looking at the line graphs provided, it’s easy to see that both home runs and walks follow a similar trajectory. The height of base-on-balls were the 2000 season, the same year there was a record set on number of home runs hit. Home runs took a dip in 2005, and so did walks.

What does this mean? Do steroids both help hitters jack home runs AND helps their eye sight? Well, probably not. There is a much simpler answer to why home run stats and walks have followed a similar trajectory path while strike outs continue to go up. The size of the strike zone has changed.

According to a 2007 study done by two historians at the University of Nebraska-Lincoln (Larger Strike Zone, Drug Testing Reduced Hitting Baseball Since 2000) changes to how umpires call strikes and balls has had a huge impact. The larger the strike zone, the lower the offensive production. The opposite is true as well. Small strike zone means hitters have the opportunity to wait on the perfect pitch, and when that pitch does not come, they take a walk.

This study, along with the QuesTec pitch-tracking system showed that the enforced strike zone between 2002 and 2006 was larger compared to 1996 – 2001. Then, in 2009 a new system called Zone Evaluation was implemented in all ballparks, which is based on much better technology. This system grades umpires on accuracy and is used to determine which umpires receive post season assignments. And, since 2009, strike outs have been at an all time high — and the strike zone has gotten enormous.

So, have steroids contributed to the inflation of offensive numbers in Major League Baseball? Yes, without a doubt. But, a change to the strike zone — which also coincides with important dates in the MLB timeline — have also played a huge part.

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