Lineup Protection

Interesting article arguing that lineup protection in baseball exists. This runs counter to the sabermetric wisdom that lineup protection is a myth: Past research (if I recall correctly) has determined that having a better hitter on deck does not, over a significant number of plate appearances, result in a better hitting experience (more hits, walks and bases per plate appearance) than having a worse hitter on deck.

The author sums up this theory and suggests his criticism of it:

[J.C.] Bradbury’s regression analysis [in his book The Baseball Economist] attempts to measure the effect of the on-deck hitter’s quality on the current batter’s outcome (his regression model has the on-deck hitter’s OPS on the right-hand side and the current batter’s outcome on the left-hand side). This approach is intuitive; in fact, my initial instinct might be to perform similar research. However, at bat outcomes involve many moving parts (where the ball lands, reaction of the defense, and luck, to name a few), and Bradbury is trying to measure the effect of an outcome-based rate (OPS) on another outcome. Thus, if there is some noise or randomness within the data, the problem would be compounded in the findings.

Certainly this is true. But this is why a sufficiently large sample size is needed for the study. The question is: Is the set of data used to analyze lineup protection inadequate? The author seems to assume that it is, although that’s never been my impression.

He suggests examining pitch-by-pitch data to see whether batters see more “good” pitches (pitches in the strike zone, and fastballs rather than breaking pitches) with a better hitter on deck rather than a worse hitter. His analysis says yes:

The protection production function seems to tell us conflicting stories. The “input” findings show that protection exists, but the “output” evidence suggests that protection does not exist. So, which answer is correct? In addition to the potential randomness issue discussed earlier, outputs suffer from one other relative disadvantage – the mere volume of data being studied is different. Analysis at the per-pitch level (inputs) employs about four times the number of instances as per-at bat level analysis (outputs). Thus, while prior research may (or may not) point us in the right direction, I would argue that the production function’s inputs push us much closer to the truth.

I don’t buy this argument. The question at hand, as I see it, is not “Does having a better hitter on deck cause the pitcher to throw pitches to the batter that are easier to hit (i.e., more advantageous to the batter)?”, but rather, “Does having a better hitter on deck cause the batter to produce more runs?”

If we grant the result of his analysis (if not the conclusion he draws from it), though, then it does raise an interesting question: If a better hitter on deck causes the pitcher to change his approach, then why don’t batters in such situations experience better outcomes than in other situations? Are pitchers changing their approaches in a manner which is not actually useful? Is there something here that players and teams don’t yet understand and which might be exploitable?

He wraps up with a broader point:

I want to be clear about my broader argument. The sabermetric community will benefit as it moves away from its relatively strict reliance on outcomes and outputs. Events on the field of any sport involve a great deal of processes. While outcome data (e.g., much of what you find online at great sites such as retrosheet and baseball-reference) have generally been more widely available, a full picture of economic analysis in the future will rely much more heavily on whole processes and their inputs.

While both inputs and outputs can be interesting, neither is inherently more or less interesting than the other. It depends on what you’re trying to study. This fellow has failed to persuade me that the input side is as important as the output side in the case of lineup protection.

(I learned about this post through the Red Sox Mailing List. And boy does the list’s page need updating!)

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