JunkStats Year In Review: All Qualified Hitters Ranked by OPP

Out Prevention Percentage is a tweak on On-Base Percentage that measures the actual number of outs a player makes. Which players did the best (and worst) at preventing outs in 2011?

The key differences between OBP and OPP are

1. OPP does not count reaches on error (ROEs) and catcher’s interferences (XIs) as outs
2. OPP counts double plays hit into (GIDP) as 2 outs instead of just 1.

So a player who hits into a lot of double plays (like Albert Pujols) will do worse in OPP than in OBP, while a player who hits into a lot of ROEs (like Ryan Braun) will do better in OPP. For more on what OPP is and how it is calculated, check out this glossary

OPP+ is just a simple league-adjusted version of OPP. The MLB average OPP+ is 100, and is indexed to the league average OPP (which was .309 this year). Each point above 100 is equal to 1% above average.

Here is how each qualified hitter (min. 502 PAs) fared in OPP. Bold indicates a league-leading total (NL or AL):

It’s fascinating to see where OBP misleads us. Here are a few examples:

• Ichiro and Yadier Molina: These two players were 39 points apart in OBP, as Ichiro was at .310 and Molina was at .349 (MLB average: .321). Yet they made outs at the same rate, as both had a .309 OPP, which is right at league average. If you look closely at the columns on the right, you can see that Ichiro had as many ROEs as double plays (11), while Molina reached on an error just twice but had 21 GIDPs. That’s a swing of 19 outs prevented, mostly due to the huge difference in speed between the two players.
• Albert Pujols and Andrew McCutchen: These players had nearly the same above-average OBP (.366 for Pujols, .364 for McCutchen). But there was actually a huge gap in their rates of making outs. Because McCutchen reached on 8 errors and hit into just 7 double plays, his OPP (.364) was actually a bit higher than his OBP. Pujols, on the other hand, led MLB in GIDPs (with 29) and reached on just 5 errors, leaving him with a comparatively low .329 OPP. That 25-out difference explains how McCutchen can rank in a tie for 18th in OPP while Pujols is clear down in a tie for 73rd.
• Ryan Ludwick and Edwin Encarnacion: Encarnacion has a 24-point lead in OBP (.334 to .310) but Ludwick actually leads in OPP, .317 to .309. Ludwick reached on 10 errors and 5 catchers’ interferences–which isn’t luck; he’s consistently one of the best at drawing XIs. Encarnacion reached on just 4 errors (and no XIs), plus he hit into 8 more double plays than Ludwick. That’s a difference of 19 outs.
• Vernon Wells and Alex Rios: While Wells had the lowest OBP among qualified players (.248), it was his former teammate that posted the worst OPP (.237). Wells reached on 5 more errors than Rios and hit into 12 fewer double plays, though that couldn’t save him from the bottom of the leaderboard, as he still tied for the 3rd-worst OPP (.250).

And so on. Just keep in mind when you use OBP that, while it generally does an excellent job of estimating a player’s ability to prevent outs, it isn’t technically doing that. Some players (especially fast ones) are underrated by OBP and others (high-double-play types) are overrated by it.