Comments on: The Problem with Fielding Percentage This and that about baseball stats. Tue, 16 Jul 2013 17:01:55 +0000 hourly 1 By: kds Sat, 13 Nov 2010 17:18:14 +0000 Phil @ 42,

I think it is more likely that the manager would see that he was leading the league in PO and Assists, and vote for him to win a Gold Glove. If he could hit a little he might win.

More seriously, I think it is very important to try to remove the effects of fielding when rating pitchers. There is strong reason to believe that the big improvement in ERA for TB between 2007 and 2008 was mostly fielding.

By: Jimbo Sat, 13 Nov 2010 16:35:25 +0000 Johnny thanks for the explanation regarding Cano. I guess the key bit of info is that no otehr 2nd baseman played everyday or even close to it it seems.

By: Phil Haberkorn in Indiana Fri, 12 Nov 2010 23:54:49 +0000 Re: post #1...."good teams tend to avoid errors, not that avoiding errors helps you win ballgames...."
I think that statement is a hypotenusal impossibility, or a circular illogism, or whatever you call it.
Ummmmmmmmmmm, OK, so how do you define "good teams" if it's not based on winning ballgames, which you do by avoiding errors? What's the last "good team" that led the league in errors? What's the last last-place team that led the league in fielding percentage?
They say good pitching beats good hitting, which explains the 1966 World Series.
But does anybody's fielding "formula" take into account the effect lousy pitching has on fielding?
A shortstop commits more errors this year than last year, but he's getting more chances because the pitchers are giving up more ground balls, so is the shortstop having a bad year? Maybe bad enough that the manager starts thinking about moving him to first base?

By: Phil Haberkorn in Indiana Fri, 12 Nov 2010 23:42:33 +0000 OK, how would you have rated me as a Gold Glove candidate in my church softball league? One season our second baseman was my little brother, Little League age, and I was 18 playing first base. I'd have to go to my right more often for ground balls and flip the ball to him as he raced for first to beat the runner, but the runner sometimes beat him to the bag - so even though I fielded the ball, no assist was recorded because the batter got credited with a hit. Next year, the second baseman was only a year younger than me, quick as a cat, so I never took more than one step to my right, so now he's the one racking up the assists. We're getting more outs, and my fielding percentage was about the same but now it's based on more putouts, so did I have a down year that first year, or am I less likely to get Gold Glove consideration the second year just because we have a second baseman who can reach more of his "territory" and the stats never reflected my range during either year? I need to know, because I'm asking the League Commissioner (Dad) to act in the best interests of softball and overrule the award voting ... (I think there was a lot of ballot-stuffing in Hicksville which I believe skewed the results).

By: Johnny Twisto Fri, 12 Nov 2010 16:55:48 +0000 Robinson Cano led the league in putouts, assists, and fielding pct. , but his Rtot for the year is "0" and the advanced fielding stats don't show him to be a great 2nd baseman it seems (in 2010).

How is this possible?

1. He led the league in PO and A in large part because he played every day. Only one other 2Bman in the league played more than 90% as many innings as Cano.

2. PO for a 2Bman are not that important. Someone else in this thread or one of the similar ones mentioned that he thought Cano was catching a lot of popups this season which Jeter could have taken. Most PO are either routine plays (routine pops, receiving the throw on a force at 2nd) or discretionary (taking the popup that anyone could have taken), or both.

3. Assists are more important, as most of them indicate the successful fielding of a groundball and throw to first. But, refer back to (1). Cano had a lot of assists because he played a lot of games. Of the 13 AL 2Bmen who played at least 500 innings, Cano was 9th in assists per inning.

4. Fielding percentage is not that important. From the team's perspective, there is no difference between a grounder that is reached but booted, and a grounder that is not reached. Both result in a man on first. Traditional stats do not count the play not made against the defender, even though the result is the same. In fact, the result might be worse for the play not made -- runner on first can go to third -- while an error might keep the ball in the infield and the runner on first stops at second. (Throwing errors which allow runners already on to advance extra bases are different, of course.)

5. Going back to (3), we still have not fully accounted for Cano's opportunities. The innings he played are only part of it. If the ball is never hit near him, he can't make any plays. So the advanced stats attempt to estimate his opportunities. UZR and DRS use a record of where every ball was hit (see kds's post 36). Total Zone (Rtot) goes off the play-by-play records. Essentially these systems are trying to break the field into zones, determine how many balls are successfully fielded when hit into a specific zone, and determine how many balls Player X successfully fielded.

6. But these advanced systems are estimates. They try to eliminate the bias of just using your eyes, but they can have their own biases (again see #36). By and large they get it "right" (look at all the players rated highly, you will find they are generally considered good fielders, and vice versa). But for any individual player, the system can miss. Maybe the player faced an inordinate number of balls right on the edges of his zone, or hard-hit balls not recorded as such. People who know more about them could probably think of other reasons.

7. I agree that Cano turns the DP well, but no major league 2Bman turns it poorly. I doubt the difference between Cano and the worst would be more than 10 completed DPs over the course of the season, maybe worth a few runs.

8. Cano only rates average this season by TZ and UZR, but he does rate well by DRS.

I think the advanced numbers have value, but no one should take one single-season number as gospel. I advocate looking at multiple numbers and supplementing that with subjective opinion.

By: BSK Fri, 12 Nov 2010 16:01:35 +0000 When I was 12, I was playing CF. I had a sinking liner hit right at me. I charged, slid, but couldn't come up with the catch. I was able to knock the ball down and keep it in front of me. When I got back to the dugout, the scorekeeper asked if I had hit the ball with my glove before it hit the ground. "I'm not sure. I think I did," was my reply. "Then it's an error," he said.

That was all I needed to know to conclude that errors were dumb. Had I simply laid up and played the ball on the hop, I wouldn't have gotten an error. By trying and ultimately failing to catch the ball, which might not have been catchable at all given my positioning, I was charged with an error. Again, I was 12.

By: Jimbo Fri, 12 Nov 2010 07:51:14 +0000 Hey, I'm relatively new to the advanced fielding stats. Can someone help me out here?

Robinson Cano led the league in putouts, assists, and fielding pct. , but his Rtot for the year is "0" and the advanced fielding stats don't show him to be a great 2nd baseman it seems (in 2010).

How is this possible?

I also think he looks extremely competent with the glove, and his double play turn looks as good as they come with a great arm.

By: kds Fri, 12 Nov 2010 07:12:44 +0000 Also, RF is poorly constructed. It is put outs plus assists per 9 innings. But this mixes apples and oranges. For an outfielder the put outs are what we want. Adding in assists just puts together two somewhat different skills that we should want to measure separately. For infielders it is worse. We want to know balls successfully fielded, but assists include the pivot on double plays, relays from the outfield and rundowns in the basepaths. Put outs include pop ups (easy), line drives, (often not so easy), throws from other infielders, throws from outfielders to double off a baserunner, pick offs and caught stealing, as well as ground ball plays made unassisted. If we have play by play info, as from a scorecard, then we can sort out a lot of this. Some plays can be made by more than one player, e.g. pop flies and caught stealing at 2nd. Some plays can be made in more than one way, like ground balls near 1st. The 1B can take it unassisted, or throw to the pitcher covering. There is a lot of noise in RF, some of it can be reduced of eliminated with play by play data; but we still don't know enough from that to say that 2 players faced the same number of balls that were easy, medium and hard to field.

By: kds Fri, 12 Nov 2010 05:06:55 +0000 Jason @34, let me expand on JT's correct answer @35. The NL average last year was that 31% of all balls in play, (not counting bunts), were ground balls. For the Cards it was 36%. This is a huge difference. If we did not adjust for this the StL infielders would look great, and the outfielders bad, because the opportunities were distributed so much differently from the average. When someone says that player A is better because he had more RBI than player B, we are using the unstated assumption that all else is equal. Like RBI, this is not true for simple RF.
As John Autin said @22, pitchers K rate GB/FB tendencies, and # of RH batters vs LH batters faced can all significantly change the number of balls hit to a particular fielder. There are also possible park effects; think of the large foul ground in Oakland, or all the balls that would have been caught in other parks but bounce high off the wall in Fenway.
Overall, the biggest problem in judging a players defense is trying to figure his opportunities. UZR and Dewan's plus/minus, (often called DRS), get data in which someone has given a direction and a speed estimate, (soft, medium, hard), for all ground balls, and spot landed or fielded for outfield balls with a notation of line drive or fly ball. There is subjectivity here and there likely is systemic bias. (Calling balls not fielded hard hit, or line drives, while calling balls fielded more often softly hit or fly balls.) There now exists Field f/x, at least at some parks, which would give us exact figures for ball direction, speed and hang time, as well as fielder positioning. At this time the information gathered has not been publicly released as the earlier Pitch f/x data was from the begining.

By: Johnny Twisto Thu, 11 Nov 2010 21:51:30 +0000 It's biased because not all players have the same number of opportunities.