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How the Cubs Have Fared on the Mistake Index

Photo courtesy of Jeff Curry-USA TODAY Sports

A couple years ago, I created something I call the Mistake Index, in which I attempt to measure mistakes that both teams and their opponents make, with the assumption that teams that make fewer mistakes have more success. I’ve written about this in several places, most recently here, and I’ve also created a data visualization that I update daily. In particular, going into 2015 I was very interested to see what difference Joe Maddon might have in reducing these mistakes, since it’s no real secret the Cubs haven’t played the best fundamental baseball in recent memory.

I group mistakes into three basic categories. The first set are pitching mistakes, which includes hit-by-pitches, balks, passed balls, and wild pitches. I also have a category called errors-pitching, in which any of these four categories or a walk directly allow a run a score. For example, if a pitcher balks with a runner on third, that’s an error-pitching and a mistake—it’s double-counted, but since a run scored, I’ll live with that. However, if that balk did not cause a run to score, it’s just a mistake. In addition, any time the opposing pitcher is walked also falls in the error-pitching category.

I’m not a huge fan of the save, but blown saves have special resonance with me, since I consider them the ultimate mistake by taking a game in which a team is leading and giving it away to the opponent. There are games in which multiple blown saves are awarded, and I think If I were to give weights to mistakes (and I probably should, but that’s a different discussion) I’d probably give greater emphasis to blown saves.

This table summarizes the pitching mistakes for the Cubs and their opponents since 2009 through the first 25 games:

BP Mistakes 1

So far in 2015 (games through Tuesday, May 5), the Cubs have five blown saves, nine HBP, five wild pitches, one passed ball, and one error-pitching, or a total of 21 pitching mistakes, compared to 27 mistakes that Cubs opponents have made. This stands in stark contrast with recent years since the Cubs have made fewer pitching mistakes than opponents for the first time since 2011.

My second group are fielding mistakes:

BP Mistakes 2

Just for fun, I’ll add another picture illustrating a little-known fact, which is the relationship between errors and unearned runs:

BP Mistake 3

This chart shows two things, the first (the blue bars) being the percent of errors that eventually turn into unearned runs, which is fairly consistent around 55-57 percent. The second (the red line) is the percent of total runs that are unearned, which has stabilized at around 8-9 percent.

I wrote a brief piece recently here at the site discussing the fact that the Cubs are among the best so far this year in both not allowing unearned runs and also scoring unearned runs themselves. Chances are pretty good neither of these trends can be sustained, but so far this year, the Cubs are not allowing teams to capitalize on their errors. I won’t speak for everyone, but I had reservations going into 2015 regarding the Cubs defense. No matter how it’s viewed, it hasn’t been great—those 21 errors are among the most in baseball, Baseball Prospectus defensive measures don’t portray the Cubs’ defense in a flattering manner, but so far it hasn’t hurt them.

The last measure I call base-running mistakes:

BP Mistakes 3

Base-running mistakes are any time a player is attempting to advance on the basepaths and is thrown out. In last Friday’s game against the Brewers, Starlin Castro was thrown out at third trying to advance on a single by Chris Coghlan. It was a bang-bang play that required four things to occur—Ryan Braun had to field the ball cleanly, make a good throw to Luis Jimenez, who had to field the ball cleanly and apply the tag. All of this occurred, but it’s still a mistake in my calculations. In actuality, it’s not a mistake as much as a play that went wrong—things happen, and teams will have far worse outcomes if they stop taking any risks on the field, but I’m merely describing what a base-running mistake is while acknowledging not all are wrong or bad plays.

In addition, force outs are not included in these totals, since it’s not the runner’s fault the ball was hit directly to an infielder. Bunting mistakes are any attempt to bunt, be it for a sacrifice or a hit, in which the runner isn’t advanced. The vast majority of these bad bunts are made by pitchers, who apparently have lost the ability to bunt. Trying to bunt for a hit with the bases empty is not included, because there’s nothing wrong with trying to do that—teams usually bat around .350 or so when bunting.

My inclusion of stolen bases in the index has varied over the years, and in my current version I don’t include them, since there’s such a wide disparity in the use of the running game by teams. Pickoffs are a different matter, since players should be cognizant on the basepaths no matter if they’re trying to steal or not. More often than not, pickoffs are lapses in attention and are quite likely the epitome of correctable mistakes.

This table puts all the mistakes together:

BP Mistakes 4

At the core, a mistake is either taking an additional base or giving opponents an additional base at no cost. Since I believe positive outcomes should have a positive measures, the Cubs difference of 31 fewer mistakes than their opponents reflects making fewer mistakes, giving away fewer bases, which logically should lead to fewer runs allowed, earned or unearned. It’s not a perfect index, but it’s not set up to be the definitive answer to questions vexing baseball since its inception as much as a quick way to see if reducing mistakes can lead to more victories. It seems to—check on the Win Pct Correlation tab in the data visualization referenced earlier in this post to see how well it works.

Of course, it’s not a lockstep correlation, but few things in sports (and life) are. A different data visualization shows the correlation between mistakes and team winning percent for all teams from 2009-2014, and a quick review shows the Minnesota Twins have done well in keeping mistakes to a minimum and not had good records to show for it. Seeing the consistent manner in which the Twins had kept mistakes to a minimum did intrigue me when they fired Ron Gardenhire after last season, but then I tempered that by thinking, “What are the chances the Cubs would get rid of Rick Renteria after one season? That’s crazy talk!”

We know how that turned out. Refer to the data visualization above and see how the Rays fared when Maddon managed them, and generally speaking, they made fewer mistakes than their opponents. It’s difficult to tell which is the chicken and which the egg—do teams make fewer mistakes because they have better players, or are teams better because they make fewer mistakes? The answer is somewhere between the two, but I think it tends more toward the fewer mistakes=better team line. Many of these things, especially baserunning mistakes, can be coached away or improved with greater concentration.

For comparison’s sake, the White Sox have made 72 mistakes (23 pitching, 31 fielding and 18 baserunning, including 14 being thrown out on the basepaths, tops in the league). Their opponents have made 67 (28-24-15). Making mistakes is rarely a good thing, and the Sox offense so far this year hasn’t enabled them to overcome them. This is probably one of the reasons why the talk of replacing Robin Ventura has begun, because it’s one thing to lose, another to look like you don’t belong on the field.

I’m not stating that individual mistakes can be eliminated, but I do contend they can be reduced. Every time one of these mistakes is eliminated, opponent teams aren’t given a base for free and have to work harder for their runs. The 2015 Cubs have been able to reduce their mistake so far this year, and if they can keep it up, they’ll go a long way toward staying relevant in the playoff picture.

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