Consistency in relation to baseball players is often claimed but rarely quantified. I’ve noticed this to be especially true with regards to starting pitchers, likely because they're the ones with the ball in their hands to start every game, so there’s an inherent sense of direct control and power over the outcome. With that sense comes a great deal of scrutiny over who can get the best results day in and day out.
As such, instead of just repeating rhetoric and assumptions about who is and who isn’t consistent, I decided to take a look at the five primary Dodgers starters with the goal of providing evidence and clarity to the discussion.How Will Consistency Be Measured?
Created by Bill James, it’s a bit of an antiquated statistic now. However, while it isn't the best measure of a pitcher's effectiveness, I’ve actually found it useful for the purpose of determining consistency. Game score can give a solid overall rating of the quality of a start, something that using rate statistics like ERA/FIP/SIERA can't accomplish.
So using game score, I’ll be taking the ratings of the Dodgers starters from 2010 to 2012 in order to get a solid sample size. From those ratings, I'll be getting a range, a mean, and a standard deviation for each pitcher.
The standard deviation is the important number to pay attention to here, as that number is actually what has been dubbed the Consistency Factor.
Note: For Chris Capuano and Aaron Harang, I only used 2011 & 2012 starts due to injuries in 2010 that I thought could skew their data.
The higher the Consistency Factor, the more inconsistent the pitcher is, and the league average consistency factor is around 16, which puts the Dodgers rotation at extreme ends of the consistency spectrum.
At a glance, it’s easy to see that Clayton Kershaw, Chris Capuano, and Aaron Harang are consistent start-to-start. However, Chad Billingsley and Ted Lilly are as volatile as they come.
In short, if you need to settle a debate between which pitchers are most consistent, then here's the order:
Chris Capuano > Aaron Harang > Clayton Kershaw > Ted Lilly > Chad Billingsley
Consistent ... But To What Purpose?
Consistency is universally considered a positive quality, as it carries at positive connotation. However, consistency is only good if … well … you’re good at what you’re doing.
Unsurprisingly, that also applies to starting pitching, as it turns out that being consistent is only a positive mark on the ledger if you’re an elite arm to begin with.
In fact, this all goes back to the old axiom: A run saved is worth more than a run scored. Mr. Inconsistent will have more low-run starts, and more high-run starts. However, as long their RAs remain equal, Mr. Inconsistent's low-run starts will add more value than his high-run values will lose him.
The difference can actually be pretty great, so why does conventional wisdom say otherwise? I think the answer is actually pretty simple. Consistency seems like a good trait. A consistent player looks like he knows what he's doing, like he's put it all together, like he's a "professional." Inconsistency, meanwhile, is associated with younger players and those who have yet to figure the game out. So we naturally tend to assume that consistency is good. More so, even if the quality start had never been invented, we would still notice that some starters pitch well day-in-day-out, while others are more up-and-down. The first group looks consistently good, giving the impression that it's better, though that might not be the case.
So in application, it's actually better to be a volatile pitcher than a consistent one if you aren't an elite pitcher.
Granted, the advantage of being inconsistent is marginal, but if a pitcher allowed more than three runs per nine, volatility has shown to be more good than bad.
The takeaway is that, at the end of the season, the better statistical profile wins out as the better overall pitcher, regardless of consistency. So despite conventional wisdom, the journey in this case isn't as important as the end result.
I researched this article not only to settle debates over who was or was not actually consistent, but to see whether or not it even mattered, and I think I've successfully achieved both goals.
We've found out that the trio of Clayton Kershaw, Chris Capuano, and Aaron Harang are all near or in the top 10 most consistent pitchers in the league, and that Chad Billingsley and Ted Lilly both find themselves near or in the top 10 most inconsistent pitchers in the league. We've also discovered that consistency itself doesn't actually help or hurt the overall value of pitchers, so it's rather pointless to stress about.
While consistency is not necessarily a positive in reality, it absolutely is to fans who watch every game. They’d much rather see a stable pitcher give up three runs every seven innings than a guy who may be great or may be terrible at random. I don't necessarily fault them for that either, as I see the same things they do. After all, it's only an instinctual preference, because it gives the fan a sense of excitement to always be within a few runs, rather than be down seven in the third inning or something of that nature. However, while it can be frustrating as fans to deal with the ups and downs in the short-term, it’s the long-term results that matter, and I think we’d all be better off to remember that.