Jon Shepherd: A primer on pitch framing (or how a ball is worth 0.17 runs)

You may have heard the term "pitch framing" bandied about lately. In this guest blog, we hope to make the concept behind pitch framing and its implementation more familiar to you.

How does one figure out how to measure how well a catcher frames pitches? Well, it is like any idea. Ideas go through several stages in order to be implemented. Typically, an idea for a design is created in order to address a desire. These ideas are then tested for their soundness against what we already know. From there, the design proceeds from those conceptual stages to an applied testing, or beta testing, phase. The model is rigorously tested to look for any weaknesses in the design. Once that reaches a certain level of quality, the idea is implemented until a better approach arrives.

Fielding metrics are like that. Beginning in the 1870s, when Henry Chadwick and Al Wright preached the importance of range against the rising popular opinion that errors were a more important consideration. They lost out to that sentiment and generations of baseball men and fans were drawn to the fool's gold that is fielding percentage. At Camden Depot, we refer to the folly of fielding percentage as the Rubbermaid Paradox. That is, a Rubbermaid container standing upright in left field will have a perfect fielding percentage, collecting every fly ball that falls into it, while being the worst left fielder in baseball. Thankfully, this issue is being addressed by people that have followed Chadwick and Wright's lead. It is why we now have a growing number of defensive metrics like defensive runs saved, ultimate zone rating, defensive efficiency and others that are slowly chipping away at the fielding conundrum.

While the methodologies differ for those metrics, they do agree that the ideal metric can be expressed as an expected run value. It makes sense: Runs are how a game is decided. The most common way to do this is to perform multiple regression analysis and find how runs are associated with different events in order to calculate how many runs are expected from an event.

A simple way to do this is to lay out baseball events on one side of an equation with runs scored on the other side for each team and then solve for each variable. This can be a tiresome calculation, but, quite merrily, FanGraphs reports it for you. Perhaps, that was too much of a leap of mathematical faith, but it does make sense and several major league teams use this process. Many of these metrics hover between beta testing and full implementation, depending on the club. Hopefully, if the math lost you, its use in front offices and in the dugout did not.

Anyway, from the FanGraphs table, the value of a walk for 2014 is a positive change of 0.69 expected runs. In other words, if you subtract the number of expected runs after a runner walks prior to him walking, then you would have 0.69 runs. For clerical purposes, this number is adjusted for the negative contribution of outs, so a strikeout is worth a change of zero runs. With a walk (or four balls) equaling 0.69 runs, then a ball is worth 0.17 runs.

This leads us to the point of this entry: pitch framing. An umpire incorrectly calling a strike a ball is a loss of that value, while a ball being called a strike is a gain of that value. Pitch framing tries to give credit to a catcher for being able to turn balls into strikes. This does appear to be a skill because catchers show yearly repeatability in their performance. This repeatability, as well as Orioles catcher Matt Wieters' performance was discussed in this article at Camden Depot. There certainly is a good bit of variability in those numbers, but the results do make sense based on general impressions.

However, there are certainly issues with measuring pitch framing and one should see it more as a litmus test. Responsibility is shared by a pitcher and a catcher, and there is a great deal of work trying to sort out exactly who should earn credit. At Camden Depot, we do discuss this metric and will be reporting on Wieters' performance as the year progresses. Also keep in mind, Wieters' defensive value extends beyond pitch framing. How he blocks pitches, throws out runners, and handles outfield throws are also important.

Jon Shepherd blogs about the Orioles at Camden Depot. Follow him on Twitter: @CamdenDepot. His thoughts on the O's appear here as part of MASNsports.com's continuing commitment to welcome guest bloggers to our little corner of cyberspace. All opinions expressed are those of the guest bloggers, who are not employed by MASNsports.com but are just as passionate about their baseball as our roster of writers.

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