The Home Run Derby Effect
While currently watching the 2017 T-Mobile Home Run Derby I am watching in anticipation of a Judge vs Stanton final. There was some question as to if Judge would participate in the derby. It is always a worry for fans, teams, and players that participating in the derby will have a negative effect on their second half swings. It is always fun in the moment to see massive home runs, but does it have an adverse effect? For an experiment, I took the first half and second half OPS of both the winner and runner-ups of the past ten home run derbies. From there I did a T-test in R for the two means. The results are as follows:
Null Hypothesis: 1st half OPS equals 2nd half OPS
Alternative Hypothesis: 1st half OPS is greater than 2nd half OPS
At a 95% confidence interval p = .6933 therefore we fail to reject the null.
From the past 10 year, there is no significant evidence showing that there is a difference between first half and second half OPS from derby winners and runner ups. This is very telling since you would expect second half numbers to be worse than first half due to some regression from elite first halves. What about if we do first half and second half homeruns. Since due to injury some of the hitters did not have full second halves. For a difference of 200 at bats I added on 4 home runs. The results are as follows:
Null Hypothesis: 1st half home runs equals 2nd half home runs
Alternative Hypothesis: 1st half home runs is greater than 2nd half home runs
At a 95% confidence interval p = .005 therefore we reject the null.
This tells us that there is significant evidence that the derby contestants will have a dip in home run production following the break. This test was not perfect. Adding 4 homeruns is a conservative estimate.
This was just something fun to look in to. There is no reason to take any of this too seriously. These hitters will most likely do just fine in the second half. Aaron Judge is still an animal and may not be from this planet. Simply enjoy these stars compete in this fun competition.