As offense is continually decreasing, a popular solution to increase the offense has been the shrinking of the strike zone. The solution that many have proposed is to reduce the low strike, which has been called more and more often since the implementation of QuesTec and later, Zone Evaluation. This would require a change in the wording of the strike zone, and in theory it could increase offense, which could potentially help increase the popularity of the game.

This may be a surprise to some, but re-wording the strike zone is a common occurrence throughout the history of the game. OK, maybe not common, but it does happen on occasion. The first implementation of a strike zone was in 1887. Before 1887 batters would ask where they wanted the ball delivered and pitchers had to throw it there. There was no official definition of the strike zone.

The main question I tried to answer was: how did each re-wording of the strike zone affect the run environment, if at all? There is no guarantee that there has been any correlation in each case. I think it’s a good theory and I would tend to believe that it would affect the run environment, that being said, there are many factors that go into the run environment, and the strike zone is merely one of them.

The first chart is a representation of the run environment leading up to 1887, when the strike zone was officially defined. The definitions of the strike zone were found on Baseball Almanac. The data for all the charts was provided by Baseball-Reference. The X-axis is the year and the Y-axis is the average runs per game.

Take this data for what you will. I personally don’t think it truly reveals a ton about the strike zone’s effect but it is a data point.

“A (strike) is defined as a pitch that ‘passes over home plate not lower than the batsman’s knee, nor higher than his shoulders.”

After 1887 there was a relatively steep drop in the run environment before it went back up. I’m not entirely sure the data reveals anything as the chart is rather noisy. In this chart, other factors probably were conducive to the fluctuation in run environment.

“A fairly delivered ball is a ball pitched or thrown to the bat by the pitcher while standing in his position and facing the batsman that passes over any portion of the home base, before touching the ground, not lower than the batsman’s knee, nor higher than his shoulder. For every such fairly delivered ball, the umpire shall call one strike.”

This chart again isn’t precisely indicative that the change in strike zone had an impact on the run environment. The game was still in its infancy and there was a lot of fluctuation before things stabilized in the mid 1900s.

“The Strike Zone is that space over home plate which is between the batter’s armpits and the top of his knees when he assumes his natural stance”.

This data point gives us more information. There was a pretty drastic drop from 1950-1952 in offense. In fact it was almost an entire run of offense that dropped and it makes sense. This was the first time there was a concrete definition of the strike zone. The umpires now had something to go on. It did stabilize though until 1963, where there was a slight drop in offense, obviously unrelated to the strike zone.

“The Strike Zone is that space over home plate which is between the top of the batter’s shoulders and his knees when he assumes his natural stance. The umpire shall determine the Strike Zone according to the batter’s usual stance when he swings at a pitch.” This rule was implemented in 1963.

As you can see there is no real change or affect from the rule change or the re-working of the rule. What you will also be able to conclude from the upcoming charts is that the re-wording of the strike zone doesn’t exactly have any effect on the offensive environment.

The strike zone was then again altered in 1969; “The Strike Zone is that space over home plate which is between the batter’s armpits and the top of his knees when he assumes a natural stance. The umpire shall determine the Strike Zone according to the batter’s usual stance when he swings at a pitch.”

“The Strike Zone is that area over home plate the upper limit of which is a horizontal line at the midpoint between the top of the shoulders and the top of the uniform pants, and the lower level is a line at the top of the knees. The Strike Zone shall be determined from the batter’s stance as the batter is prepared to swing at a pitched ball”

“The Strike Zone is expanded on the lower end, moving from the top of the knees to the bottom of the knees (bottom has been identified as the hollow beneath the kneecap).”

The offense, as you can see, does take a rather significant and consistent dip after 1996. However, this is probably not due to the re-working of the strike zone, or rather, one cannot tell that it is due to the re-working of the strike zone from this chart.

There is, as we all know, another element to this strike zone saga and it’s the implementation of QuesTec. QuesTec was implemented in 2002 and was not well received by umpires. In 2003, they actually filed a grievance about the use of QuesTec, which was resolved in 2004.

The evidence displayed by the data above doesn’t suggest that QuesTec had a direct link to offensive production. What it rather indicates is there was a drastic shift in offensive production after 2006. 2006 was the year where Zone Evaluation was implemented in baseball. Zone Evaluation was deemed to be a more accurate way of judging the strike zone. Its implementation also has a direct correlation with a constant decrease in offense, which has not ended. The goal was to force umpires to be more accurate and to adhere to the definition of the strike zone, which was last altered in 1996. In 1996 the definition explicitly dictated that the strike zone should expand downward from the top of the knees to the bottom of the knees. This seems to perhaps be the biggest impact against offense.

There are obviously other extreme factors to consider. For example, the aggressive testing of steroids and other performance-enhancing drugs. It seems most of us, including myself, like to believe that we are playing in a much cleaner game, which has affected the offense as a whole. Pitchers are throwing harder than ever and if that wasn’t enough, most advance metrics seem to favor pitching and defense. These are all elements to consider that have affected the offense.

That being said, there is an undeniable connection between the enforcement of the strike zone and the drastic drop in offense. In previous years, when the strike zone was re-worked, there were no real correlations with regards to offense, apart from 1950, where the strike zone was initially defined. The correlation is rather with technology and the strike zone. It’s highly probable that the umpires in years past ignored or disregarded the changes of the rule. They just kept calling the strike zone like they always did. The implementation of Zone Evaluation forced them to change, which had a direct effect on the offense. Changing the strike zone should have a rather drastic effect, especially now that we have Zone Evaluation to keep umpires accountable.