Catching independent pitching, evaluating pitchers without catchers


As pitch framing data becomes more and more advanced, we have to completely re-evaluate pitchers. We have fielding independent pitching, which allows pitcher performance to be separated from fielding performance. As our understanding of catching and pitch framing improves, we need to re-evaluate the performance of pitching to incorporate catching data. Thus, I have created the new metric Catching Independent Pitching, or CIP.

Fundamentally, the problem with fielding independent pitching is that catcher contributions have never been considered. There is an obvious and notable difference between a good and a poor pitch framer, something that has never been considered by FIP or ERA. Thus, I have set out to create this new metric, Catching Independent Pitching (CIP)

When it comes to pitching statistics, the statistics often do not accurately evaluate pitcher skill, instead, contributions by the rest of the team are also often counted. For instance, the pitching win has little to do with pitcher performance, there was even an instance where the pitcher threw a no-hitter, but still recorded the loss. Wins and losses are fundamentally cannot be used to evaluate pitcher performance, since it considers the rest of the team’s defensive and offensive contributions. Wins are only accurate when used to evaluate the team as a whole, through its win-loss record.

Earned Run Average faces a similar problem. It is commonly used to evaluate pitchers, but as a stat, ERA is also effected by the contributions of the defense. It is my opinion that ERA is a good representation of a team’s defensive capabilities, as the combination of the defense and the pitcher. However, as a stat to evaluate the pitcher alone, ERA is fundamentally flawed and does not give an accurate representation.

Fielding Independent Pitching was thus created as a better representation of the skill of a pitcher. Instead of looking at earned runs, something that the team as a whole contributes over, FIP looks at things that the pitcher supposedly controls himself. Namely strikeouts, home runs, walks, and hit my pitches.

Fundamentally however, with increasing knowledge of the catcher’s contribution to a pitchers performance, we can see that Fielding Independent Pitching is still a fundamentally flawed statistic. Supposedly FIP measures the contribution of the pitcher alone, but since a catcher’s control of the strike zone heavily influences called balls and strikes, FIP actually measures the capabilities of the pitcher- catcher combo, and not just the pitcher.

Thus, I have created a new statistic, Catching Independent Pitching, or CIP. It partially compensates for the contribution of the catcher, but as we can see later, unfortunately, it is still a work in progress, and further research has to be done to isolate pitcher performance with catcher performance.

What is Catcher Independent Pitching?

Before we begin, let’s first consider the formula for Fielding Independent Pitching:

Let HR be the number of home runs allowed, BB be the number of walks, HBP be the number of hit by pitchers, K be the number of strikeouts, IP be the number innings pitched, and C be a constant to normalize FIP with ERA. The formula is:


When it comes to home runs allowed or walks, we can assign responsibility solely to the pitcher. Yes, the opposing hitter contributes to hitting the home run, or drawing the walk, but when it comes to strikeouts and walks, the catcher plays a major role. After all, if a good catcher can turn a borderline ball into a strike, a ball slightly outside the zone on a 3-2 pitch would become a strikeout instead of a walk.

Thus, we would have to consider the effects that the catcher has on the pitcher’s statistics. From the statistics, we can see that a top notch catcher contributes quite a bit to his team’s success. For instance, Brian McCann, in his 2008 season contributed 33 runs to his team’s success. If we convert that to wins, that’s an extra 3.3 wins in a single season!

In order to quantify the catcher’s contribution to the pitcher’s performance, first we have to quantify it, and normalize it over a long enough period. For instance, consider the example of Jose Molina. In 2013, Molina caught 749.1 innings for the Rays , over this period of time, he had 4786 framing chances, and contributed and extra 174 strikes . That is approximately 0.232 strikes per inning. If every umpire called balls and strikes perfectly, this wouldn’t exist. I would consider a replacement level catcher to be one who does not influence called balls and strikes in any way. Molina is thus worth an extra 0.232 strikes per inning over a replacement level catcher.

At this point, we have to consider exactly how much is a single strike worth. In some situations, 1 strike is worth 1/3 of an out. If the catcher is capable of framing 3 straight balls into strikes, instead of a 3 – 0, we have a strikeout. On the other hand, an extra strike is worth effectively nothing, for instance, if a catcher frames a ball into a strike, to make the count 0 – 1 instead of 1 – 0, it would mean nothing if immediately after, the hitter hits a home run on the second pitch of the at bat.

Overall, I place the importance of an extra framed pitch to be a quarter of a strikeout. Thus in our example, David Price threw 186.2 innings. If we assume that Molina caught every single inning Price threw, Molina has contributed an approximate 43.152 extra strikes (I rounded innings numbers down to the closest integer). These extra 43.152 strikes can be said to be worth an extra 10.788 strikeouts.

I call this part the "catcher’s contribution", or CC for short. If we let FS (framed strikes) be the rate of extra strikes per inning a catcher frames, and IP as the innings pitched that this catcher caught, the catcher’s contribution can be defined as:


Of course, the contribution of the catcher can be both positive and negative, good framers would have a positive number, bad framers would have a negative number.

Catching Independent Pitching can thus be redefined as:


By removing the contribution of the catcher from the pitcher’s numbers, we can derive a better representation of a pitcher’s skill. Just like how FIP was created to separate the separate the pitchers’ contribution from the contribution of the defense, CIP can be used here to separate the contributions of the catcher from the pitcher’s numbers.

In our previous example, Jose Molina has a CC of 0.116. David Price has thrown 186.2 innings in 2013, with a FIP of 3.03. Assuming that Molina caught every inning Price threw (which isn’t true), Price should have a CIP of 3.15. Since we are assuming that a "standard" catcher would have no effect on called balls and strikes, in most cases, a pitcher’s CIP should closely mirror his FIP.

Of course, the above calculation is flawed because I simply assumed that the same catcher caught the pitcher for every single inning. Which is of course, in most cases, not true. We can compensate for that by separately calculating the Catcher Contribution. For instance, if 2 catchers caught the same pitcher, we can calculate his CIP with two individual CCs:


Problems and difficulties

Of course, my current formula for CIP is still very much a work in progress. Isolating the catcher and the pitcher and evaluating them separately is very difficult. I have run into a few difficulties when devising this benchmark, which I have listed below.

Data is a problem for me. I don’t have easily accessible data how exactly how many innings did each individual catch for a pitcher, so I had to resort to assuming that the starting catcher would catch every single inning that the pitcher pitches. Hopefully as pitch framing research becomes more widespread, pitcher-catcher matchup data would become easier to find.

The next step would be to separate the catcher’s pitch framing contributions by pitcher. The current data that I have from Baseball Prospectus is for the catcher catching every single pitcher on the team. Obviously, the difficulty in catching different pitchers are different, and the analysis would be much improved if there is data on how well a catcher can frame each individual pitcher’s pitchers.

Finally, after considering pitch framing, there is still a gigantic portion of the catcher’s contribution that we still cannot quantify. Catchers call pitches, and the importance of pitch calling cannot be understated. Good catchers can call a sequence of pitches to baffle and deceive opposing hitters, they can prevent pitchers from continually announcing their presence with authority, Nuke Laloosh style. As far as I know, it is still impossible at this point to evaluate the pitch calling capabilities of catchers.


Separating pitcher performance from the performance of his teammates is a long running theme in pitching statistics. However, current benchmarks still cannot separate the effects of the pitcher and the catcher. Thus, I have created Catching Independent Pitching, or CIP to attempt to separate pitching from catching.

So far, CIP is still an early "prototype" so to speak, so if you have any suggestions, or if you would like to collaborate, please drop me comment in the comment section. I love feedback and a good conversation!

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