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The Mistake Index

Does the number of mistakes teams make and their ability to capitalize on opponent mistakes correlate well with team success?

Why is Ryan Raburn celebrating? Read the first paragraph.
Why is Ryan Raburn celebrating? Read the first paragraph.
Jason Miller

On May 21st, Al Alburquerque was pitching for the Tigers in the bottom of the 13th inning against the Indians with the score tied 10-10. With the bases loaded and Ryan Raburn at bat, Alburquerque balked, allowing Asdrubal Cabrera to score the winning run. Yes, the winning run was . . . balked in. If for some reason the Tigers miss making the playoffs by one game, this might be the game they look back on in sadness mixed with a healthy dose of disbelief and confusion. The walkoff balk is alliterative enough that if this happened on a frequent basis it would have entered baseball lexicon -- it hasn't.

Some time ago I wrote a post discussing my Mistake Index, where I place miscues that occur in a game in one place to see if there is any correlation between mistakes (or lack thereof) and winning. Clicking this link opens a Google Docs spreadsheet that will be updated daily (or very close to it). If turnovers are anathema to football, basketball and every sport, why isn't it the same in baseball? Shouldn't as much focus and attention be given to team mistakes as in other sports?

Baseball is different in that mistakes don't cause the ball to be turned over to the other team, but the negative effects of mistakes are equivalent to turnovers in other sports. Advancing a base on a balk, scoring with the bases loaded on a hit by pitch, being thrown out trying to stretch a double into a triple, something similar occurs in all instances -- a base is given or taken away, essentially at no cost to the other team. Turnovers have the dual effect of both denying one team the ball and giving the other a free chance to score, and baseball mistakes give or take bases away and thus deserve scrutiny.

Mistakes are grouped into three broad categories -- pitching, fielding and base running and are described in the column headings of the spreadsheet. In addition to common measures, there are some I created like errors in pitching (eP), which are events like hit by pitch, balks, wild pitches, walks or passed balls that directly lead a run to score -- for example, the Alburquerque balk was both a balk and an eP, since it led directly to a run being scored. eBB are walks that eventually score, which I hesitantly added this year since I seem to be hearing announcers talk about this far more. Any base runner reaching first has around a 38 percent chance of scoring, and singling out the walk underplays this fact.

Reached on error (ROE) errors (E) and unearned runs (unER) are the usual categories, and putting errors and unearned runs side-by-side shows how often errors translate into runs -- historically, it's around 55-57 percent. Errors in base running (eBR) are any occasions when runners are thrown out on the bases, the ever-popular TOOTBLAN effect. It doesn't include force outs, because those aren't the runner's fault. Errors in bunting (eBU) are any attempt to bunt with runners on base that doesn't result in a sacrifice bunt or a hit. Bunting with the bases empty is not included.

Many of these items can be found with a little digging at or FanGraphs, but not in one place. Also, my index shows opponent's mistakes as well, which are not easily found without utilizing play-by-play data. For example, if Michael Bourn hits a grounder to Manny Machado that is bobbled, chances are his speed will allow him to reach first on an E5. However, if it's Paul Konerko batting, Machado has time to grab the ball, get a good grip, count the seams on the ball, head into the stands for a beer and a hot dog, sign some autographs, scope out the crowd and then walk the ball over to Chris Davis for the putout. I contend that not only is mistake prevention a good thing for teams, capitalizing on mistakes opponents make is equally important -- in my example, Bourn's speed produces an advantage the Indians can capitalize on.

This illustration from a game between the Braves and Cardinals on May 18th shows how mistakes can pile up. The Cardinals brought in Trevor Rosenthal with a 5-4 lead in the ninth inning to close out the game, and this is what happened:

Batter Pitcher RoB Play
Freddie Freeman Trevor Rosenthal --- Single to LF (Line Drive to Short LF)
Chris Johnson Trevor Rosenthal 1-- Strikeout Swinging
Andrelton Simmons Trevor Rosenthal 1-- Popfly: SS
Ryan Doumit Trevor Rosenthal 1-- Double to RF (Line Drive to RF Line); Freeman to 3B
Evan Gattis Trevor Rosenthal -23 Intentional Walk
Jordan Schafer Trevor Rosenthal 123 Walk; Freeman Scores; Doumit to 3B; Gattis to 2B
Ramiro Pena Carlos Martinez 123 Wild Pitch; Doumit Scores; Gattis to 3B; Schafer to 2B
Ramiro Pena Carlos Martinez -23 Walk
Jason Heyward Carlos Martinez 123 Groundout: 1B-P

With runners on second and third Rosenthall issued an intentional walk to Evan Gattis, after which the wheels fell off as he walked in Freddie Freeman, threw a wild pitch allowing Doumit to score and was lifted from the game. Two mistakes turned into a third (a blown save) and a loss for the Braves.

But does keeping mistakes to a minimum translate into winning? I use this simple formula:

Opponent Mistakes - Team Mistakes

Positive values mean teams make fewer mistakes than their opponents, and negative values mean teams make more mistakes than their opponents. If the Mistake Index is effective, teams with winning records should have a positive value, and those with losing records negative ones and can provide another method to measure team effectiveness.

No one measure tells the entire story of a team's performance, but the Mistake Index puts several disparate events together in one place to see if reasonable conclusions can be made. The ultimate goals in baseball are run scoring and run prevention -- taking advantage of opponent mistakes can allow runs to score, and keeping mistakes to a minimum can prevent them. The Mistake Index allows one to see how effective teams are at not just minimizing their mistakes but capitalizing on opponent mistakes. Bookmark the spreadsheet and see how your team performs over the course of the season.


The Mistake Index adapted from play-by-play data at Any errors in compiling the data are the author's.

Scott Lindholm lives in Davenport, IA. Follow him on Twitter @ScottLindholm.