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# New Yankee Stadium's Statistical Effect: Are The Yankees' Stats Inflated?

Timothy O'BrienCorrespondent IJune 7, 2009

(This article is 6 pages of length.  There is a lot of statistical data and numbers.  If you are interested only in the results and analysis of those results, I would read only the last two pages)

A lot of ink has been spilled discussing the power numbers being put up at the New Yankee stadium. The most criticism is aimed at the right field fence which is considered by many to be far too short.

The Yankees list the dimensions the new park as identical to those of the old park.  This, however, is the result of strategic measuring. The distances are taken at certain points in the park which are identical.

In fact, the new ball park is smaller overall. Here, you can view the two park's dimensions superimposed on each other. These dimensions were taken using high resolution satellite photos.

Right field is the same in the corner. However, in the old park, right field would just be a few feet from the foul line and keep on an outward trajectory. In the new park, the fence juts out less than the old park and then continues straight across, without getting any deeper. There is an electronic scoreboard in the right field fence, preventing much trajectory change.

The fence is also slightly shallower in a small section of left field.

Baseball commentators have blamed the boom in home runs at the New Yankee Stadium on it's dimensions. Not only did I want to find out if that was true, but I also wanted to see how the individual Yankees' stats were affected by the new ball park.  This paper analyzes how the new stadium has effected Yankee offensive output.

Procedure:

This section will explain how I did the math. It will explain how I figured out what Yankee players are on pace for, and how I figured out what the difference between  their currents year's output versus their past output. If you trust I did the math correctly, and just want to get to the meat of the stats, feel free to skip this section.

If you want to see how I did it, please read on. I will label the next section when it begins.

To measure how the Yankees were statistically affected by the New Yankee Stadium, I used the 162 game averages of the Yankee players over their entire career measured against what they are on pace for this year if they were to play 162 games.

It's simple. I am comparing what these Yankee players would do, if they did what they've done so far this season for a complete set of 162 games, to what they have done on average in 162 games in the past.

I used Baseball-reference to retrieve 162 game averages as well as 2009 season statistics.

Here is a  simple example of how I figured out how a player was affected by the new stadium.

Suppose I have an average of 20 home runs per 162 games. Also suppose every 162 games, I average 600 at bats.

Now, in this example, I have 200 at bats so far in the 2009 season and in those at bats I have 10 home runs.

First, I will figure out, based on how many more at bats I usually have in a 162 game season, how many home runs I am on pace for in the 2009 season if I play 162 games.

Here, as mentioned earlier, I average 600 at bats in a 162 game season. I will take 600 and divide it by 200 (the amount of at bats I have so far in 2009 season), which comes out to three. I will call this number the multiplier.

To figure out how many home runs I an on pace for in 2009 if I play 162 games, I will multiply the "multiplier" by the amount of home runs I have so far. In this case, I would use three multiplied by 10 (the amount of HR I have so far).That comes out to 30. So, If I were to play a 162 game season at the pace I am on in the current season, I would hit 30 home runs.

To figure out the increase over my average for this year, I simply figure out the percent increase of my current rate over my average output. I normally hit 20 home runs in a 162 game season. Now I am on pace for 30 home runs, which marks a 50 percent increase in home run output this year.

For the purposes of this analysis, I used only players who have over 100 plate appearances this season. I also excluded players who don't have a significant enough history to measure their past averages.

This excluded players like Xavier Nady and Jose Molina because they didn't have enough plate appearances this season. It also excluded Brett Gardner, because while he has enough at bats this season, he has no history to measure against. This left me with nine players.

I also only used runs scored, home runs, and runs batted in as statistical measures.

A note on 162 game averages: They will be inflated numbers, and they are. They are not a player's average season. As most player do miss games, they are their stats over 162 game periods.

Here is baseball-references definition of 162 game averages.  "This is an attempt to condense each batter's career into a single season's worth of stats. With batters this is easy. Just take their career games played and divide by 162 and then divide their career totals by that factor."

Individual Players Statistical Differences

2009 Season Stats as of June, 5, 2009

100 at bats
14 runs scored
8 home runs
26 RBI

Career 162 game averages

545 at bats
83 runs scored
25 home runs
97 RBI

On pace for in 2009 if 162 games played at this pace

76 runs scored
44 HR
141 RBI's

Percent change comparing 2009 pace against average 162 game pace

Eight percent decrease in runs scored
76 percent increase in home runs
45 percent increase in RBI

Mark Teixeira

2009 Season Stats as of June, 5, 2009

194 at bats
37 runs scored
16 home runs
47 RBI

Career 162 game averages

613 at bats
102 runs scored
37 home runs
123 RBI

On pace for in 2009 if 162 games played at this pace

117 runs scored
50 HR
148 RBI's

Percent change comparing 2009 pace against average 162 game pace

15 percent increase in runs scored
35 percent increase in home runs
20 percent increase in RBI

Robinson Cano

2009 Season Stats as of June, 5, 2009

223 at bats
38 runs scored
9 home runs
32 RBI

Career 162 game averages

631 at bats
88 runs scored
18 home runs
88 RBI

On pace for in 2009 if 162 games played at this pace

108 runs scored
26 HR
91 RBI's

Percent change comparing 2009 pace against average 162 game pace

23 percent increase in runs scored
44 percent increase in home runs
Three percent increase in RBI

Derek Jeter

2009 Season Stats as of June, 5, 2009

217 at bats
33 runs scored
7 home runs
25 RBI

Career 162 game averages

656 at bats
119 runs scored
17 home runs
82 RBI

On pace for in 2009 if 162 games played at this pace

100 runs scored
21 HR
76 RBI's

Percent change comparing 2009 pace against average 162 game pace

16 percent decrease in runs scored
24 percent increase in home runs
Seven percent decrease in RBI

Alex Rodriguez

2009 Season Stats as of June, 5, 2009

92 at bats
13 runs scored
7 home runs
22 RBI

Career 162 game averages

623 at bats
127 runs scored
44 home runs
128 RBI

On pace for in 2009 if 162 games played at this pace

88 runs scored
47 HR
148 RBI's

Percent change comparing 2009 pace against average 162 game pace

31 percent decrease in runs scored
7 percent increase in home runs
16 percent increase in RBI

Johnny Damon

2009 Season Stats as of June, 5, 2009

202 at bats
43 runs scored
11 home runs
33 RBI

Career 162 game averages

641 at bats
113 runs scored
15 home runs
75 RBI

On pace for in 2009 if 162 games played at this pace

136 runs scored
35 HR
105 RBI's

Percent change comparing 2009 pace against average 162 game pace

20 percent increase in runs scored
33 percent increase in home runs
40 percent increase in RBI

Nick Swisher

2009 Season Stats as of June, 5, 2009

167 at bats
33 runs scored
10 home runs
32 RBI

Career 162 game averages

557 at bats
94 runs scored
28 home runs
87 RBI

On pace for in 2009 if 162 games played at this pace

110 runs scored
33 HR
107 RBI's

Percent change comparing 2009 pace against average 162 game pace

17 percent increase in runs scored
18 percent increase in home runs
23 percent increase in RBI

Hideki Matsui

2009 Season Stats as of June, 5, 2009

164 at bats
18 runs scored
8 home runs
22 RBI

Career 162 game averages

602 at bats
97 runs scored
24 home runs
104 RBI

On pace for in 2009 if 162 games played at this pace

66 runs scored
29 HR
81 RBI's

Percent change comparing 2009 pace against average 162 game pace

32 percent decrease in runs scored
21 percent increase in home runs
22 percent decrease in RBI

Melky Cabrera

2009 Season Stats as of June, 5, 2009

148 at bats
22 runs scored
6 home runs
22 RBI

Career 162 game averages

555 at bats
72 runs scored
10 home runs
64 RBI

On pace for in 2009 if 162 games played at this pace

83 runs scored
23 HR
83 RBI's

Percent change comparing 2009 pace against average 162 game pace

15 percent increase in runs scored
130 percent increase in home runs
30 percent increase in RBI

Team/Side of the Plate Changes

After calculating each individual players statistical changes, I then wanted to see how the overall team has been affected. To do this, I added up the percent changes and divided it by the total number of players (in this case nine players). This gave me the average change in output per player. I did this for runs, home runs and RBI's.

• These nine Yankee average change in runs scored was an increase of .33 percent (note, it's not 33 percent,  but .33 percent).
• These nine Yankees average change in home runs was an increase of 43 percent. I noticed that Melky Cabrera alone had an increase of 130 percent, seemingly a statistical outlier. Without Caberera, the other eight Yankees averaged an increase of 32 percent in home runs.
• These nine Yankees had their average change  in RBI totals increased by 16 percent.

In addition to the overall team effects, I wanted to see how the new stadium affected left handed hitters versus how it affected right handed hitters.  Keep in mind, out of these nine, only two players were considered right handed hitters (Derek Jeter and Alex Rodriguez). All switch hitters were considered left handed hitters as that is where they get a vast majority of their at bats as well as their statistics.

Left-Handed Hitters

• The seven left-handed Yankees considered average a 7 percent increase in runs scored.
• The seven  left-handed Yankees considered average a 51 percent increase in home runs. Without Melky Cabrera, the remaining six left-handed hitters average a 38 percent increase in home runs.
• The seven left-handed Yankees considered average a 16 percent increase in RBI.

Right-Handed Hitters

• The two right-handed Yankees considered average a 15 percent decrease (note, it's a decrease) in runs scored.
• The two right-handed Yankees considered average a 16 percent increase in home runs.
• The two right-handed Yankees considered average a 4.5 percent increase in RBI.

Analysis

As it turns out, offensive numbers overall have increased significantly in the New Yankee Stadium. Runs, home runs, and RBI are all up by at least 16 percent, with home runs seeing the most significant change with an increase of 43 percent.

Certainly there are other factors to consider in this analysis, with one of the largest increases is seen in the stats of Melky Cabrera. He also happens to be a young player who is likely improving at this point in his career. Maturation certainly played a role in Cabrera's improved numbers. However, his surge cannot be ignored for purposes of this analysis.

As for the effects of the short right-field porch, lefties have a distinct advantage in the new park as compared to the old one. Left-handed hitters saw an increase in all three statistical categories. Right-handed hitters saw an increase in home runs and RBI, but a decrease in runs scored.

Moreover, where left-handed and right-handed hitters shared an increase in home runs and RBI, left-handed hitters increased at a significantly greater rate than did right-handed hitters.

As the numers increased as a team, there are other factors at work when comparing righties to lefties.

For one, I only used two right handed hitters in this analysis. A small sample size is tough to judge. However, they also happen to be the players in the analysis with the longest history to measure against.

Additionally, Derek Jeter is an older player who's statistics are less likely to increase and could possibly be declining. Alex Rodriguez on the other hand might be so good and have such a strong statistical history that it would be difficult to increase his output with a venue change.

With all that said, the number don't lie. The Yankees offensive numbers, especially the power numbers, have increased in large percentages this season when compared to the past.

Certainly one could argue this might be due to a maturation of young players, or a strong lineup finally put together. One could also argue that perhaps everything is coming together at one time.

What makes me believe it is due to the stadium is how significant the difference between left-handed hitters and right-handed hitters is. Left-handed hitters increased home runs at a 51 percent rate per player, righties at a 16 percent clip. Left-handed hitters increased RBI's by 20 percent per player, righties at a 5 percent clip. Left-handed hitters increased runs scored by a rate of 7 percent per player, while righties actually decreased at a 15 percent rate.

This clearly indicates that the short right-field porch is having a very significant impact on player output. This in turn, indicates to me that a significant increase in overall production is not simply the result of factors mentioned earlier, but rather the effect of a smaller ballpark.

This analysis in no way means to state the Yankees have any unfair advantage at all.  Both teams still  have to play each game in the same park, so the short right field advantages Rays and Red Sox hitters as much as it does Yankee hitters.

What it should tell you is individual Yankee offensive statistics are inflated by the new ballpark. This could in fact be a Yankee disadvantage as they will have to pay higher prices for reluctant pitchers in the future (see Mike Hampton's and Denny Neagle's contracts with Colorado).

Teams around the major leagues need to keep the New Yankee Stadium factor in mind when they are dealing with ex-Yankees in the offseason. When an ex-Yankee players agent is trying to ask for money that a player with comparable stats is receiving, General Managers need to keep where those players obtained those numbers in mind.