Project by: Henry (10th Grade)

Faculty Advisor: Jacqueline Baker

Stadium Analysis

For my honors project, I posed the question: Do teams hit better in closed baseball stadiums or open baseball stadiums? My hypothesis was that closed baseball stadiums produce slightly more offense (hitting) than open stadiums. I speculated this  for two reasons: first, closed stadiums have a controlled warm climate, and their fields are mostly artificial turf instead of grass. A controlled climate means that there is no wind which could blow the ball back towards field, and the humidity and temperature are constant, meaning the ball will travel further because of the low humidity and warm temperature. Artificial turf allows batted balls to elude fielders more easily because the balls bounce off the surface faster than traditional grass. My data showed that—on the whole—closed stadiums do benefit offenses slightly more than open stadiums; my hypothesis was proven.

To prove my hypothesis, I compiled data on certain teams’ Runs Per Game and Batting Average. I chose the teams based on which stadiums I used. I chose five open stadiums and five closed stadiums to be analyzed.

My goal was to find out whether there was a significant difference between the offensive output of open stadium teams versus closed stadium teams, and if different environments (such as climate) in those stadiums had any effect. There are many more open stadiums than closed stadiums, so I could not reliably compare every stadium in Major League Baseball. The closed stadium teams I picked were the Tampa Bay Rays, the Toronto Blue Jays, the Arizona Diamondbacks, the Seattle Mariners, and the Milwaukee Brewers. The open stadium teams were the Oakland Athletics, the Chicago White Sox, the Los Angeles Dodgers, the Cleveland Indians, and the Texas Rangers. To be as uniform as possible, I chose stadiums with similar dimensions. I averaged their combined home plate-to-center field distance, which was ≈400 feet. I then took the 5 stadiums whose center field distances were closest to 400 feet. Now I needed the specific stats of those stadiums/teams.

I wanted to measure “offense”, but that is an extremely broad term, so I chose two stats to focus on. These were Team Batting Average (BA) and Team Runs Per Game (RPG). A Batting Average is the number of at bats a player had in a game, divided by the number of hits that player got; Team Batting Average is just the team’s total at bats divided by their total hits. Batting Average assesses pure hitting (or offense), because it shows a hitter’s (or team’s) success against a pitcher, which is fundamentally offense. Contrarily, Runs per Game assesses a team’s run production, which is essential to a team’s success; whoever scores more, wins the game. Runs per Game is more important than Batting Average when judging offense because a team can win with a low Batting Average and high Runs per Game, but not vice versa. Due to this, I chose to focus solely on Runs per Game, even though the data collected for Team Batting Average was very similar to Runs per Game.

The average of the RPG data shows closed and open stadiums were virtually equal in terms of run-production. (4.51 RPG for closed, 4.5 RPG for open).  I compiled data on Team Winning Percentage (TWP) during these years to see if it could explain my findings, and it partially did. Particularly, the TWP graph follows similar trends to the closed part of the RPG graph from 2003 to 2011, while also corroborating the 2004 open Stadium spike. The RPG graph shows both open and closed at relatively high levels until a sudden dropoff in 2009 and 2010. These high levels can be attributed to steroid use by the players, which was widespread from the mid 1990s to 2007. Steroids make players stronger and less susceptible to lengthy injuries, thus increasing their offensive performance. In 2006, Commissioner of Baseball Bud Selig appointed former federal prosecutor George Mitchell to investigate banned substance use in baseball. In December 2007, the “Mitchell Report” was released, which detailed over 80 Major League players—including many famous players— who had used steroids and/or Human Growth Hormone illegally since 1990. Major League Baseball then implemented much more effective testing for such illegal substances, and steroid use has since been virtually eliminated. The sudden decrease in offensive production in 2009 and 2010 can be attributed to the lack of performance-enhancing drugs, but it can also be attributed to fast pitches. According to Travis Sawchik of the Pittsburgh Tribune-Review (triblive.com), a 2014 study showed that the average pitch velocity was 90.9 MPH in 2008 versus 92 MPH in 2013. The 1.1 MPH difference may not seem like much, but in reality it can mean the difference between striking out and hitting a home run: “The speed increase is tilting the competitive balance in favor of pitchers, and in favor of teams with more velocity,” Sawchik wrote. This, along with the lack of steroids could explain the offensive dip in both open and closed stadiums.

The tiny 0.01 difference in closed versus open stadiums’ Runs per Game does not prove my original hypothesis that closed stadiums would be slightly more conducive to offense than open stadiums. This combined with the small sample size (the sample size is small because 2 of the 5 closed stadiums I used opened in 1998, and I chose a 15 year sample size) means that my data did not conclusively prove my hypothesis.

There has been an explosion of hitting in baseball recently. The predominant theory is that steroid use gave hitters a sizable advantage over pitchers. However, I always thought that hitting in different environments had been a factor: I had never seen a study done on the differences between closed and open stadiums, so I conceived of this project. After completing this study, I have realized that I should have focused on more than one variable, as I was attempting to solve a very complex issue (the rise in hitting). Also, having a larger sample size would probably produce results that are more conclusive. Overall, this process has been a nice experience because it combined two interests of mine—baseball and math—and forced me to make my own conclusions about a relevant issue in baseball.

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PROPOSAL:

Please write a description of the project you are proposing. Why do you want to take this on, and what do you hope to learn?

Investigating the Offensive Differences in Traditional Stadiums Versus Closed Stadiums: I am interested in the different teams in baseball and their intricate qualities. The teams that play home games in closed stadiums may have an inherent advantage or disadvantage compared to the other teams that play in open stadiums. I want to know whether this is true or not.

What is your proposed outcome? How will you be able to demonstrate successful completion of this Project?

The project will be completed when I can deduce whether or not my hypothesis has been proven, and when I can figure out the reason(s) why.

Honors Project T3_1 2017 Runs Per Game – Sheet1-2-wivh5l