Lucky and Unlucky Baseball Stats
A couple of years ago, economics professor and die-hard Braves fan J.C. Bradbury got sick of watching Chipper Jones rip line drive after line drive right into the gloves of the opposition. One of his beloved Braves was having a great season at the plate and it wasn't showing up in the stats because of something as simple as bad luck.
Bradbury decided to do something about it. In an effort to filter out the effects of luck -- both good and bad -- on batting statistics, he came up with a system called PrOPS (Predicted On-Base Plus Slugging Percentage.)
By now most of us are comfortable enough with regular old OPS. It combines on-base percentage and slugging percentage into a neat little number that Joe Morgan doesn't care for very much. Bradbury went one step further and took the play-by-play data provided by a company called Baseball Info Solutions to predict what a player's OPS should be based on the type of balls that he hits. A player who hits a lot of line drives, for example, would be rewarded, while a player who hits a lot of infield popups would be penalized.
"Sometimes balls that should be doubles are caught, and sometimes a popup falls for a hit," says Bradbury, who teaches at the University of the South and runs Sabernomics.com. "PrOPS takes all the things that players do that normally translate into success and judges them only on those factors."
Because breaks tend to even out as the sample size of data grows, PrOPS is a powerful tool in figuring out which players will benefit and which ones will suffer as their statistics regress to the mean. For example, Reds outfielder Austin Kearns posted a real OPS of .785 last season, but his PrOPS was .840, indicating that he was a better hitter than his statistics were giving him credit for. This season, Kearns' real OPS is almost identical to his PrOPS from last season: .852. If you look back at the top 25 underperformers for 2005 as calculated by PrOPS, you'll find others who have improved this season, including last year's leader, Jason Giambi, and Mike Lowell.
So who have been the luckiest and unluckiest hitters this season? Let's take a look (you can find these yourself at The Hardball Times):
2006 Top 10 Luckiest Hitters According to PrOPS
Player, OPS, PrOPS (Difference)
1. Gary Matthews Jr., .934, .762 (+.172)
2. Joe Mauer, .986, .856 (+.129)
3. Ichiro Suzuki, .876, .762 (+.115)
4. Alex Rios, 1.019, .906, (+113)
5. David Wright, .971, .863 (+.108)
6. Matt Holliday, .993, .886 (+.107)
7. Miguel Cabrera, .997, .895 (+.102)
8. Orlando Cabrera, .818, .724 (+.094)
9. Grady Sizemore, .921, .835 (+.085)
10. Scott Rolen, .970, .890 (+.080)
2006 Top 10 Unluckiest Hitters According to PrOPS
Player, OPS, PrOPS (Difference)
1. Frank Thomas, .877, 1.043 (-.165)
2. Phil Nevin, .729, .893 (-.164)
3. Adam Dunn, .970, 1.123 (-.154)
4. Jason Lane, .745, .882 (-.138)
5. Carlos Lee, .929, 1.052 (-.123)
6. Jason Kendall, .680, .800 (-.120)
7. Adam Everett, .570, .682 (-.113)
8. Jason Giambi, 1.087, 1.198 (-.112)
9. Carl Everett, .708, .819 (-.111)
10. Justin Morneau, .815, .921 (-.106)
Albert Pujols didn't make either list, but his PrOPS deserve to be singled out for admiration on their own:
OPS: 1.193
PrOPS: 1.279
Difference: -0.085
That's right. As scary good as Pujols was hitting before getting hurt on June 3, his numbers weren't doing him justice.
After coming up with the method, Bradbury crunched the numbers for every season since 2002. It turns out that his hunch about Chipper Jones' bad luck proved correct -- Jones' 2004 season ranks as the eighth unluckiest in MLB since 2002.
Bradbury decided to do something about it. In an effort to filter out the effects of luck -- both good and bad -- on batting statistics, he came up with a system called PrOPS (Predicted On-Base Plus Slugging Percentage.)
By now most of us are comfortable enough with regular old OPS. It combines on-base percentage and slugging percentage into a neat little number that Joe Morgan doesn't care for very much. Bradbury went one step further and took the play-by-play data provided by a company called Baseball Info Solutions to predict what a player's OPS should be based on the type of balls that he hits. A player who hits a lot of line drives, for example, would be rewarded, while a player who hits a lot of infield popups would be penalized.
"Sometimes balls that should be doubles are caught, and sometimes a popup falls for a hit," says Bradbury, who teaches at the University of the South and runs Sabernomics.com. "PrOPS takes all the things that players do that normally translate into success and judges them only on those factors."
Because breaks tend to even out as the sample size of data grows, PrOPS is a powerful tool in figuring out which players will benefit and which ones will suffer as their statistics regress to the mean. For example, Reds outfielder Austin Kearns posted a real OPS of .785 last season, but his PrOPS was .840, indicating that he was a better hitter than his statistics were giving him credit for. This season, Kearns' real OPS is almost identical to his PrOPS from last season: .852. If you look back at the top 25 underperformers for 2005 as calculated by PrOPS, you'll find others who have improved this season, including last year's leader, Jason Giambi, and Mike Lowell.
So who have been the luckiest and unluckiest hitters this season? Let's take a look (you can find these yourself at The Hardball Times):
2006 Top 10 Luckiest Hitters According to PrOPS
Player, OPS, PrOPS (Difference)
1. Gary Matthews Jr., .934, .762 (+.172)
2. Joe Mauer, .986, .856 (+.129)
3. Ichiro Suzuki, .876, .762 (+.115)
4. Alex Rios, 1.019, .906, (+113)
5. David Wright, .971, .863 (+.108)
6. Matt Holliday, .993, .886 (+.107)
7. Miguel Cabrera, .997, .895 (+.102)
8. Orlando Cabrera, .818, .724 (+.094)
9. Grady Sizemore, .921, .835 (+.085)
10. Scott Rolen, .970, .890 (+.080)
2006 Top 10 Unluckiest Hitters According to PrOPS
Player, OPS, PrOPS (Difference)
1. Frank Thomas, .877, 1.043 (-.165)
2. Phil Nevin, .729, .893 (-.164)
3. Adam Dunn, .970, 1.123 (-.154)
4. Jason Lane, .745, .882 (-.138)
5. Carlos Lee, .929, 1.052 (-.123)
6. Jason Kendall, .680, .800 (-.120)
7. Adam Everett, .570, .682 (-.113)
8. Jason Giambi, 1.087, 1.198 (-.112)
9. Carl Everett, .708, .819 (-.111)
10. Justin Morneau, .815, .921 (-.106)
Albert Pujols didn't make either list, but his PrOPS deserve to be singled out for admiration on their own:
OPS: 1.193
PrOPS: 1.279
Difference: -0.085
That's right. As scary good as Pujols was hitting before getting hurt on June 3, his numbers weren't doing him justice.
After coming up with the method, Bradbury crunched the numbers for every season since 2002. It turns out that his hunch about Chipper Jones' bad luck proved correct -- Jones' 2004 season ranks as the eighth unluckiest in MLB since 2002.
posted by Mike at 6:14 AM
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