Evaluating defense has always been imperfect. Primitive statistics, such as number of errors or fielding percentage, were very flawed. Newer statistics — such as UZR and DRS — are better, but still are flawed. It takes three years for UZR data to become a reliable sample, and three years is a good amount of time for a player to completely change. DRS also has its flaws because it is partly a human calculation, and humans tend to make mistakes. However, MLBAM recently rolled out a new system of data that will enable more accurate data evaluations.
This system is still a couple of years away from being publicly accessible, but it will allow us to evaluate players better based on their defense. In other defensive data news, FanGraphs recently released new data by Inside Edge Data which you can read about here. I thought it would be interesting to take a look at the third outfielder battle between Juan Lagares and Eric Young Jr. through the lens of Inside Edge Data.
David Appelman of FanGraphs explained that Inside Edge scouts every play and then decides how easy or hard it is to make the play based on this scale:
-About Even (40-60%)
-Almost Certain / Certain (90-100%)
Obviously, this evaluation of players is flawed because — like DRS — it involves human judgment which can be arbitrary and therefore inaccurate. However, even though it may be inaccurate, it’s a new way to look at defense. Below is a table that shows how many plays players received within a specific rating on the scale, and the percentage of times they made the play in that rating on the scale. Here is how Lagares and Young are graded by Inside Edge Data:
|Player||# 0%||# 1-10%||1-10%||# 10-40%||10-40%||# 40-60%||40-60%||# 60-90%||60-90%||#90-100%||90-100%|
It’s worth noting that Lagares had more playing time last year than Young, and therefore the number of plays he has been a part of is higher. The new data pretty much agrees that on routine plays Lagares and Young are pretty much equal. However, from then on out the data actually favors Young on the tougher plays, which is pretty surprising considering Lagares had a UZR of 21.5 last year, compared to Young’s rating of -1.9.
This comparison of Lagares and Young may be a good reason why comparing players with the new data is not a good idea. The sample size is different for every player. Some players play a full season in the field, while others — like Young — only started to get regular playing time two or three months into the season. The other flaw with the new data is that it really only measures how well a player can cover his ground, doesn’t necessarily take into account how good a player’s arm is or whether or what he is doing after he fields the ball.
It’s likely that if Young got as much playing time as Lagares did then his percentages on the more difficult plays to make would decrease. This new data favors Young as the better fielder, but when you compare it to UZR and DRS, it clearly favors Lagares. This data is probably not a good way to decide how a player can add value through defense. It can indicate which players can make a lot of difficult plays, which is useful. From the Inside Edge Data point of view, Young is a better defender than Lagares. However, we know that is not really the case.