Andrea L. Buono

Andrew K. Somberg

Nicholas B. Angstman

Paul M. Sommers

Trevor B. Dodds

English

Research Papers in Economics

 
 
DERBY DROP-OFFS 
 
 
by 
 
Paul M. Sommers 
Nicholas B. Angstman 
Andrea L. Buono 
Trevor B. Dodds 
And 
Andrew K. Somberg 
 
 
 
 
March  2010 
 
 
 
 
 
MIDDLEBURY COLLEGE ECONOMICS DISCUSSION PAPER NO. 10-08 
 
 
 
 
 
 
 
 
DEPARTMENT OF ECONOMICS 
MIDDLEBURY COLLEGE 
MIDDLEBURY, VERMONT 05753 
 
http://www.middlebury.edu/~econ 
 
 
 
 
                                                                                                                                             2 
 
 
 
 
 
 
 
 
DERBY DROP-OFFS 
 
 
 
 
by 
 
 
 
 
Nicholas B. Angstman 
Andrea L. Buono 
Trevor B. Dodds 
Andrew K. Somberg 
Paul M. Sommers 
 
 
 
 
 
 
 
Department of Economics 
Middlebury College 
Middlebury, Vermont 05753 
psommers@middlebury.edu                                                                                                                                             3 
 
 
 
DERBY DROP-OFFS 
 
 
 
   Everything that you were taught not  
    to do you have to do in the home run 
    contest.  It’s either a home run or nothing. 
 
—  Ken Griffey, Jr. [1] 
July 10, 2008 
 
 
  The All-Star Game in Major League Baseball marks the halfway point in the season.  
Since 1985, the night before the All-Star Game, Major League Baseball has hosted an event 
called the Home Run Derby (hereafter, the Derby).  The six to ten invitees (many of whom also 
participate in the All-Star Game) are among the top home run hitters in baseball that season.  
These sluggers compete over several rounds of elimination to determine who can hit the most 
home runs.   
  During the 2005 Derby held in Detroit’s Comerica Park, Philadelphia’s Bobby Abreu 
clubbed a Derby record 41 homers in just three rounds.  Abreu had had a spectacular first half: an 
on-base plus slugging percentage of .955, 18 home runs, and 5.57 home runs for every 100 at bats.  
However, his second-half production declined, with an on-base plus slugging percentage of .787, 
6 home runs, and 2.26 home runs for every 100 at bats.  The decline led many fans to question 
whether his participation in the Derby caused the precipitous drop in his production.  Ken 
Griffey, Jr.’s concern is shared by other Derby invitees, hitting coaches and managers alike.  In 
the summer of 2008, five-time home run champion Alex Rodriguez (of the New York Yankees) 
turned down multiple invitations to participate in the Derby even though it was being held at 
Yankee Stadium.  “My responsibility is to the New York Yankees,” A-Rod told the media. “I 
need my swing to be at its best.” [2]                                                                                                                                             4 
 
  In this brief note, we examine whether or not the Derby adversely affects participants’ 
on-base percentage plus slugging average (OPS), the number of home runs (HR), and the number 
of home runs per 100 at bats (HR%) following the All-Star break.  In general, do common 
measures of a slugger’s performance decline after they compete in the Derby?  Is there empirical 
support for some players’ belief that constantly trying to hit home runs messes up their swing? 
  Since 1985, 180 ballplayers (90 each from the American and National Leagues) have 
taken part in the Derby.  The names of all participants are from www.baseball-almanac.com .  In 
each case, we compare a participant’s stats in the second half of the season to his stats in the first 
half.  All data on OPS, HR, and HR% are from www.baseball-reference.com .
1  In two cases  
(Hubie Brooks, 1986, 18 at bats and Ivan Rodriguez, 2000, 38 at bats), there were too few at bats 
in the second half of the season to make meaningful comparisons with the first half.  All 178 
remaining players had a minimum of 100 at bats in each half of the season (with an average 
number of 253 at bats in the second half).  The 1988 Derby was cancelled due to inclement 
weather.  And, the strike-shortened 1994 season is excluded although the Derby took place that 
July (about a month before the season-ending strike began). 
  Table 1 summarizes the results of numerous paired t-tests.  (All p-values are based on a 
two-tailed alternative.  That is, a ballplayer’s stats could rise or fall in the second half of the 
season.)  A look at the results reveals that in every single matched sample, average production 
declined in the second half of the season.  The drop-off was statistically significant for American 
League participants in all three categories — OPS, HR, and HR%.  Since the year 2000, home run 
production and the number of home runs per 100 at bats have declined for participants from both 
leagues. 
  Table 2 shows whether or not the drop-off is different for participants by league across 
different time periods.  Insofar as OPS is concerned, the decline has been far worse for American 
League sluggers over the entire 24-year period.  During the 1990s, American League participants                                                                                                                                             5 
 
not only had a lower average OPS in the second half of the season (relative to their Derby 
counterparts in the National League), but HR% was also marginally lower (p = .097).   
  Before we give Ken Griffey, Jr., Alex Rodriguez and other detractors of the Derby their 
due, we should examine differences in performance before and after the All-Star break in the year 
before the Derby.  Of the 180 Derby participants, 140 did not participate in the Derby the year 
before their participation.  Table 3 summarizes comparisons of Derby participation by half , the 
year of and the year before their participation.  The top section of the table shows how much 
better their first half of the season was in their Derby year than it was the year before.  Not 
surprisingly, all differences in OPS, HR, and HR% are statistically significant.  The middle 
section shows each slugger’s second half production in the season prior to participation and the 
season of participation.  The averages here are about the same.  That is, their slugging 
performance was no worse (and actually marginally, but not statistically, better) following the 
All-Star break of their Derby year.  And, finally, the bottom section shows that in the year before 
their participation in the Derby, these ballplayers experienced the same drop-off in HR production 
(they experienced in their Derby year), although there were no discernible changes in either their 
average OPS or their average number of home runs per 100 at bats.
2 
 
Concluding Remarks 
  There may be good reasons why some ballplayers turn down invitations to participate in 
the annual Home Run Derby.  A few have complained that the event is not good for their swing 
and causes bad mechanics that might carry over into the second half of the season. 
  The Derby drop-offs in on-base percentage plus slugging average, home run production, 
and the number of home runs hit per 100 at bats are statistically significant for all participants, 
especially since the year 2000.  Declines appear to be marginally steeper for American League 
sluggers.                                                                                                                                               6 
 
  But, on closer examination, we find a much greater difference between the first and 
second half statistics in the season of participation than in the season prior to participation.  We 
find significantly higher averages in the first half of the season of participation than in the first 
half of the season before.  And, we find that there are no differences in the second half statistics 
in the season of participation and in the season before.   
  Since ballplayers perform equally well in the second half of both seasons, we conclude 
that Derby participation did not cause the drop-off.   The first-half statistics of Derby invitees 
tend to be extraordinary.  (Otherwise, they would not have been invited to participate!)  Their 
second-half Derby-year statistics are, on average, lower (but comparable to the year before), if 
only because they exhibit a regression toward the mean.                                                                                                                                               7 
 
 
 
Table 1.  Summary of paired t-Tests 
among Home Run Derby participants 
on differences in OPS, HR, and HR%,  
before and after the All-Star break 
 
 
 
  OPS  HR  HR% 
     p-value on      p-value on      p-value on 
 Before  After  difference Before After  difference  Before After  difference 
 
 
 
All participants  .965  .921  <.001  21.472 15.556  <.001  7.047 6.194 <.001  
     (n = 178)   
 
 
AL participants  .952  .885  <.001  21.315 14.787  <.001  6.860 5.759 <.001 
     (n = 89) 
 
NL participants  .979  .957  .080  21.629  16.326  <.001  7.233 6.628  .007 
     (n = 89) 
 
 
1985-1989
* .881  .835  .065  19.482  12.593  <.001  6.305 5.004  .005 
 
    AL (n = 14)  .877  .803  .069  20.286  11.500  <.001  6.414 4.650  .013 
  NL (n = 13)  .884  .869  .587  18.615  13.769  .018  6.188 5.385  .181 
 
 
1990-1999
** .974  .919  <.001  21.375 16.413  <.001  7.210 6.457  .001 
 
  AL (n = 41)  .975  .893  <.001 21.878  16.366  <.001  7.372 6.251  .001 
  NL (n = 39)  .973  .947  .136  20.846  16.462  <.001 7.040  6.673  .254 
 
 
2000-2008 .988  .957  .029  22.338 15.718  <.001  7.145 6.349  .002 
 
  AL (n = 34)  .955  .910  .016 21.059  14.235  <.001  6.427 5.622  .030 
  NL (n = 37)  1.019  .999  .374  23.514  17.081  <.001 7.805  7.018  .035 
 
 
  *The Derby was cancelled due to inclement weather in 1988. 
**Excluding the strike-shortened 1994 season.                                                                                                                                             8 
 
 
 
Table 2.  Summary of differences 
in OPS, HR, and HR% 
between AL and NL Home Run Derby participants  
after the All-Star break 
 
 
 
  OPS change  HR change  HR% change 
  (After – Before)  (After – Before)  (After – Before) 
  
     p-value on      p-value on      p-value on 
  AL  NL  difference  AL  NL  difference  AL  NL  difference 
 
 
 
1985 – 2008  -.067  -.022  .009  -6.53  -5.30  .207  -1.10  -0.61  .113 
 
 
1985 – 1989
*  -.074 -.016  .226  -8.79 -4.85  .130  -1.76 -0.80  .260 
 
1990 – 1999
** -.082  -.026 .019  -5.51 -4.38  .418  -1.12 -0.37  .097 
 
2000  –  2008  -.045 -.020  .379  -6.82 -6.43  .804  -0.80 -0.79  .972 
 
 
    
  *The Derby was cancelled due to inclement weather in 1988. 
**Excluding the strike-shortened 1994 season.                                                                                                                                             9 
 
 
 
 
Table 3.  Summary of Derby year v. year before Derby comparisons 
on differences in OPS, HR, and HR%, 
before and after the All-Star break 
 
 
 
 
  Year before Derby  Derby year  p-value on  
 1
st Half  1
st Half  on difference 
 
  OPS  (n = 129)  .881 .971  <.001 
  HR  (n = 129)   15.364  21.271  <.001 
  HR%  (n = 129)  5.506 7.008  <.001 
 
 
______________________________________________________________________________ 
 
 
  Year before Derby  Derby year  p-value on  
 2
nd Half  2
nd Half  on difference 
 
  OPS  (n = 119)  .898 .913  .210 
  HR  (n = 119)   14.050  14.756  .228 
  HR%  (n = 119)  5.717 5.888  .425 
 
 
______________________________________________________________________________ 
 
 
  Year before Derby  Year before Derby  p-value on  
 1
st Half  2
nd Half  on difference 
 
  OPS  (n = 116)  .877 .899  .070 
  HR  (n = 116)   15.500  13.966  .009 
  HR%  (n = 116)  5.493 5.676  .373 
 
 
                                                                                                                                             10 
 
 
 
References 
 
 
 
1.  M. Antonen, “Home Run Derby not a big hit with everyone,” USA Today,  
  July 10, 2008. 
 
2.  M. Feinsand, “A-Rod to skip HR Derby, claims it tampers with swing,” 
  New York Daily News, June 30, 2008. 
                                                                                                                                             11 
 
 
 
Footnotes 
 
1.  After selecting a player, go to the gray navigation bar and click on “Splits [+]” just above  
  the player’s year-to-year “Standard Batting” summary.  Click on the player’s year of  
  participation in the Derby.  Finally, scroll down to “First or Second Half” for 1
st half and 
 2
nd half OPS and HR.  Divide HR by at bats and multiply by 100 to obtain HR%. 
 
2.  The 116 ballplayers who did not participate in the Derby the year before their 
  participation and who had a minimum of 100 at bats in each half of the season before 
  their Derby year averaged only 246 at bats in the second half compared to 279 at bats in 
the first half.  So, although their average number of home runs fell, their average number 
of home runs per 100 at bats actually rose.   
 
 
          
 
  
  
    
 
     

A-Rod to skip HR Derby, claims it tampers with swing,”

Home Run Derby not a big hit with everyone,”

Derby Drop-Offs

http://www.middlebury.edu/services/econ/repec/mdl/ancoec/1008.pdf

Derby Drop-Offs

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