Line Drive % Possible Error : Minnesota Twins 2006

Whoops, that was supposed to be “I can’t post a chart” not “a chat”.

I don’t think the scorers are to blame here. If you look at players who’ve been with the Twins for more than a year, such as Lew Ford (17.1, 16.0, 16.4), Luis Rodriguez (20.7, 19.2), Michael Cuddyer (18.6, 17.9, 20.6), and Torii Hunter (14.8, 14.3, 18.0).

Cuddyer and Hunter’s increases are mild, and coincide with career years. It’s hard to find enough evidence that the scorer is to blame. The difference in moving to a new home ballpark may be enough.

Couple problems with the argument …
1) Twins’ margin over 2nd AL team is overstated, since the #2 team to the twins was not Chicago at .201 but Cleveland at .207. [White Sox were 3rd highest.]
2) the “missing doubles” are missing because in addition to their above average LD% [.214 vs lg avg of .197], the twins were also 2nd in GB% and most importantly, last in FB% [.32 vs league avg of .37]. Line drives turn into doubles at a significantly higher rate than fly balls do, but overall about half of doubles come on line drives and about half on fly balls. So the extra doubles expected on the extra line drives would be offset by the doubles lost on fewer fly balls. The hardball times annual shows the run value of the twins LD as .38 runs per LD, vs the league average of .39, so there isn’t much reason to think that the twins had an unusual skew of outcomes on the line drives they did hit.

In sum, no reason to suspect bias from the scorers.

OK, here’s my response to your rebuttal:

1) As you note, if line drives are being misclassified, fly balls will necessarily decrease, but the twins LD (.214) plus Fb (.316) percentages = .530 which is below league average (.197 + ~.36) ~=.557. Since fly balls also strongly correlate with doubles (though not as strongly as I said originally-see below), your argument against the twins’ line drive percentage on the basis of missing doubles doesn’t hold. Note also that the Twins home park seems to have suppressed doubles the last few years. The Bill James Handbook gives a park factor of 95 for doubles. This further explains the “low” doubles total.

One discussion of batted ball outcomes is here with further links. I was in error when I said 1/2 of doubles came on fly balls; it’s actually about 35%. (I was correct when I said that half of doubles came on line drives.)
You can find fairly similar results from different datasets; in the 2006 Hardball times annual for example, where double rates of .019 per GB, .061 per OF Fly, .183 per LD were published in an article called “What’s a batted ball worth” by Dave Studenmund, using BIS data from 2002-2005.

2) about 2% of GB become doubles; they are almost all on balls down the line. This is somewhat park dependent [ these balls mostly spin into foul territory so the size and shape of Of foul territory matters]. Note that there can be discrepancies on coding a GB vs LD as well. Is a one-hopper through the infield which lands on the dirt but passes the fielder’s actual position before it bounces a line drive or ground ball? Differing services may differ in their definition … They probably all call a ball caught knee high by the 3rd baseman playing in a line drive, whereas the same ball would be a one-hopper and a grounder if he’s playing deep. But which is it if it goes through for a hit?
3) You are still not looking at the HBT LD% carefully enough. It is false that the top 3 teams in baseball are from the AL Central. For some reason the HBT gives the NL figures to 2 decimal places whereas the AL is to 3 places. Colorado at 21% is definitely part of the top 3. There are also seven NL teams with LD% rounding to 20. (6 would in the AL,topped by the white sox). Some NL team(s) besides Colorado may also exceed the white sox.

Furthermore, the AL Central is above average offensively in the league in which pitchers rarely bat. The Central teams were 2nd,3rd,5th,8th and 12th in AL in runs scored. So again with 3 of the top 5 and 4 of the top 8 it’s not intrinsically suspicious that teams in the division would also dominate the LD% list. You need to make a more careful argument than calling it a very odd coincidence as if the LD% just should be random.

The LD% percentage you are critiquing is from BIS scorers with their definition of a LD; they score line drives more generously than other services such as STATS or MLB or the source used by retrosheet. BIS supposedly uses a pool of scorers who are not tied to individual teams, so it shouldn’t be exposed to the kind of systematic error which you hypothesized.
Nonetheless, consultation of retrosheet’s version of balls in play does bring the twins well back toward the middle of the pack, which supports your view that something could be going on with the Twins LD%. Constructing Retrosheet LD% the same way HBT does, the league leader would be Toronto at .200 vs the league average of .190, with the twins 6th at .192. There are some problems with the retrosheet data (they score every SF as a fly, never as a LD, which is about 10% of their difference with BIS, and there are a handful of plays missing hit types, but this would have limited impact on teams’ relative order. Here are AL LD% based on retrosheet data:
TOR .200
CLE .199
BAL .197
BOS .197
OAK .195
MIN .192
TEX .191
KC .190
NYY .187
DET .186
SEA .185
CHW .181
TB .178
LAA .177

I am not saying that Retrosheet is right and BIS is wrong about the Twins, just indicating that they do disagree about the twins fairly significantly and this is unlikely to be
explicable just in terms of their differing definitions of what a line drive is. BIS gets points for consistency from me because it least when it comes to sacrifice flies, they seem to generally stick to their standard for coding a line drive, whereas retrosheet does not and STATS does not appear to either. [This is based on my personal review of video cross referenced against STATS and BIS game logs.] But I can’t say one way or the other whether BIS is better in general on being consistent with balls which are on their borderline between linedrives and fly balls…

This is great – thanks for following up.

Fundamentally the Twins and White Sox look like outliers, the other 3 central teams look “normal” – but I am amazed that Retrosheet actually had higher counts than BIS for Baltimore and Oakland.

We don’t know whether the “bad scoring” is on the retrosheet side or the BIS side or a mix of both. There are at least 2 other independent sources which could be pulled into this. mlb.com has files containing pbp data by game accessible on the web; there is some corruption and ~3% of their plays need to be “scrubbed” – usually by looking at video. STATS has ground ball fly and ball counts available at the team level, as well as in the game logs for individual pitchers. I don’t have scrubbed mlb.com data for 2006, but here are the other 3 for Minnesota for 2006:

BIS STATS Retro
G 2217 2243 2254
F 1493 1494 1562
L 1009 ???? 0907
B 0097 ???? 0095

So it appears as though I have a minor error in my Retrosheet query (counting dropped foul popups or something like that) because BIS adds to the correct total of 4816 but Retrosheet adds to 4818. At the aggregate level, BIS and STATS agree more on fly balls + popups than they do on ground balls! [n.b my previous comment.] And somehow sources fail to agree completely on such seemingly unquestionable events as bunts. [STATS derived information on league leaders in bunts in play can be found; they have Juan Pierre at 52 bunts in play for 2006, whereas BIS has 49. Retrosheet also has him with 49, with 2 more bunt-foul strikeouts.]

As far as I know there are no public details about how BIS scorers are assigned games, or how much cross-checking takes place. I think we know however that they score from video, whereas STATS depends on scorers at the ballpark. My own experience trying to chart hit locations from video is that it’s particularly hard on medium-depth balls hit to the oufield, because there are no obvious landmarks in view from the infield or fence as the camara zooms in on the descending ball. So I can imagine that BIS might end up having scorers who specialize by park (as opposed to by team) -this might enable them to do a better job locating these kinds of balls…