FIP and DER through History
January 24, 2004
Taking the Wayback Machine with Peabody and his boy, Sherman, we look at some historical graphs for our two favorites stats
I’ve spent a lot of time blabbing on and on about Fielding Independent Pitching (FIP) and Defense Efficiency Ratio (DER). In particular, I first explained them in this article, then I talked about my Christmas vacation with them, and I also spent some time picking one of them apart. These two stats tell us a lot about pitching and fielding, but we’ve only looked at them over the past decade or two. So I thought it would be fun to ask: how have FIP and DER behaved over time?
Well, fun for me, anyway.
So, I’ve created line graphs of FIP and DER throughout the twentieth century, in the tradition of this wonderful site, and I’ve learned a lot of Peabodyesque things along the way. Here we go:
To set the stage, let’s start with a graph of runs allowed per game:
This graph tells the history of major league baseball with which many of us are familiar. There was actually a short-lived offensive explosion in the early 1910’s, but the real offensive explosion occurred later that decade. There was also a significant half-run difference between the two leagues throughout the 30’s , the only sustained difference between them before the DH.
Offense declined during the war years but jumped back up after the war. Then we encountered the 1960’s, typified by Bob Gibson’s immaculate ERA. Next came the designated hitter, and then the offensive explosion of this past decade, in which the majors reached a level of offense equal to any decade.
So how did FIP do during these years?
As expected, FIP rose with the advent of the home run, but it is interesting that pitchers didn’t really directly contribute to that offensive explosion of the early 1910’s. In most other years, however, FIP was a primary driver of the run environment.
In fact, FIP was pretty much entirely responsible for the post-war offensive surge. And during the late 1910’s and early 1920’s, home runs and walks rose while strikeouts declined. Pretty much a FIP triple doozy.
FIP was also primarily responsible for the difference between leagues in the 30’s. In particular, NL pitchers walked less batters during that time, and AL batters hit a lot more home runs.
Okay, for a little better perspective, let’s look at Runs Allowed Per Game minus FIP. This would be runs allowed per game for which both pitchers and fielders are responsible. Let’s call it DRA, for the heck of it.
This graph is just plain interesting. Looked at in this way, there appear to be three distinct periods in baseball’s history. Well, one mini-period in the early 1910’s, in which DRA was the primary culprit for that offensive explosion.
Next, there were the two decades that began with the advent of Ruth and ended with World War Two, in which DRA was at a sustained all-time high. Beginning around 1940, DRA declined and DID NOT RISE AGAIN, even with the offensive surge of post-war baseball.
That post-war surge occurred because home runs reached levels beyond anything seen before the war.
There was a distinct difference between leagues in the 1960’s and early 70’s, but DRA primarily held steady until the early 1990’s, when it jumped again. In fact, it appears that FIP and DRA were both about equally responsible for the offensive-laden 1990’s.
What drives DRA? Well, mostly DER, of course. Here’s a graph of DER by year:
The swings are more dramatic, but when DER goes up, DRA goes down. And vice versa.
The 1960’s are interesting, by the way. Both leagues were both low-scoring environments, but the NL was more of a FIP league, while the AL was more of a DER league.
This has indeed been fun for me. The trends and periods of major league offense and defense become clearer when broken into FIP and DER. Of course, these graphs beg as many questions as they answer, but that’s half of the fun, right?
One other thought. None of these figures are adjusted for ballpark. There are no readily available ballpark factors that differentiate between FIP and DER, though James invented some for Win Shares. But we shouldn’t leave the Wayback Machine without considering them.
Now, ballpark factors are calculated such that the average for each league equals 1.00. So a graph of average ballpark factors by year would equal one each year. Pretty boring.
However, Baseball Reference keeps track of three-year running ballpark factors. So I created a graph of the change in league ballpark factors from year to year. The graph is always centered around zero, but you can see spot major changes in ballpark environments by catching large swings in the three-year moving averages.
Wow. Did I mention that this stuff is fun? There have been three distinct phases in ballpark development during major league history.
As Bill James has noted in his Historical Baseball Abstract, the modern ballpark arrived in 1909 with the construction of Shibe Park in Philadelphia, and quickly became the norm in both leagues. By 1916, virtually every major league team played in the steel-and-concrete structures that we think of as ballparks today. This must have had a significant impact on the game at that time, and I don’t think it’s a total coincidence that offense of both leagues started to increase once the ballpark environment was set.
The next big sea change in ballpark environment occurred in the late 1950’s and early 1960’s, with the westward movement of baseball franchises and MLB’s subsequent expansion. All four of the NL parks (Candlestick, Dodger, Shea and the Astrodome) were pitcher’s parks, and partly responsible for the dominance of pitching during the 60’s.
The third wave of ballpark impact came in the early to mid 1990’s, with the construction of the new Comiskey, Camden Yards, the Jake, Arlington and, of course, Coors Field. These parks tended to be hitter’s parks, as owners realized that high-scoring games attract fans.
As we’ve seen, the offense of the 90’s was driven by DRA, or fielding considerations, just as much as they were driven by FIP, or pitcher-only considerations. The new major league ballparks have not just been home run havens, but they have had a profound impact on balls hit within the park as well.
That’s all the graphs for now, folks. Time to step back into the Wayback Machine. We’ll be back tomorrow to talk a little more about the split between pitching and fielding. See you then.
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