Fangraphs Points Results by Launch Angle

A few weeks ago, I took an initial (and someone rudimentary) dive into tying Statcast data to Ottoneu. Specifically, looking at the Fangraphs Points (FGpts) format. Like in real baseball, when the ball leaves the bat with a higher exit velocity, it is more likely to produce more favorable results. This was to be expected. The way the scoring settings for FGpts was developed was through linear weights, so it would make sense that the distribution of points per batted ball ties closely to reality. Today, I am going to look at the batted balls hit though the all star break (actually, just before the break as I pulled this July 6th) and examine the expected points per ball in play on specific batted ball types. Let’s get started.

2017 Batted Ball Events
Out Single Double Triple Home Run Total Average
FGpts Value -1.00 4.60 7.50 10.30 14.00
Points Scored -45,148 65,495 33,315 4,069 45,094 102,824 1.525
wOBA 0.00 0.90 1.25 1.60 2.00 25,441 0.377
Events 45,148 14,238 4,442 395 3,221 67,444
SOURCE: Baseball Savant
-Through July 6th

So, for 2017 we can see that the average FGpts produced on a batted ball event is 1.525. Consequently, the average wOBA per batted ball event is .377 (NOTE: This is only wOBA on balls in play, and as such is higher than the league average wOBA on all plays of .321). Tying this back to basics is helpful. For example, we can see that two-thirds of the time a ball is put in play it results in an out. That singles account for nearly 64% of all hits, but 44% of all points on positive value balls in play (singles, doubles, triples, home runs). Home runs, by comparison, account for 14% of all hits, but 30% of all points on positive value balls in play.

One of the best resources in understanding statcast data is Andrew Perpetua’s xstats.org. In Andrew’s work, he classifies batted balls into 6 buckets based on their associated launch angles. For reference, here are the splits Andrew uses.

xStats.org Batted Ball Types
LA Type wOBA
0 Dribble Ball 0.176
10 Ground Ball 0.436
19 Low Drive 0.710
26 High Drive 0.730
39 Fly Ball 0.502
39+ Pop Up 0.055
SOURCE: xStats.org
-Based on 2016 Batted Balls

For the LA column, this can be read as a batted ball with a launch angle below zero degrees is a dribble ball with an average wOBA of .176. 10 corresponds to batted balls with launch angle between zero and ten, etc.

Using these same launch angle classifications, I wanted to see if the Ottoneu Scoring differed from the standard wOBA hierarchy of batted balls. As wOBA is often used as a proxy to determine FGpts value of a player, it would be helpful to know if one type of batted ball is being more heavily weighted by FGpts than by wOBA.

FGpts Values for Dribble Ball (DB)
Out Single Double Triple Home Run Total Average
FGpts Value -1.00 4.60 7.50 10.30 14.00
Points Scored -18,803 17,609 2,078 175 0 1,058 0.046
wOBA 0.00 0.90 1.25 1.60 2.00 3,819 0.167
Events 18,803 3,828 277 17 0 22,925
SOURCE: Baseball Savant, xStats.org

In examining the six batted ball types, FGpts values lined up with the wOBA hierarchy of most valuable batted ball types. Specifically examining DB.

We can see that so far in 2017, for balls recorded by statcast with a launch angle below zero, the average wOBA is .167. The average points per ball in play is .046. As we would expect, the majority of these batted balls are singles, and you can’t hit a home run on the ground. This is pretty standard. Looking at Ground Balls next, we would expect the value they produce to be greater than .046 points per batted ball, as we know that wOBA will be higher on these plays.

FGpts Values for Ground Ball (GB)
Out Single Double Triple Home Run Total Average
FGpts Value -1.00 4.60 7.50 10.30 14.00
Points Scored -4,689 19,734 3,983 288 0 19,316 2.025
wOBA 0.00 0.90 1.25 1.60 2.00 4,570 0.479
Events 4,689 4,290 531 28 0 9,538
SOURCE: Baseball Savant, xStats.org

Well that’s a nice production bump. The FGpts value gained from hitting a ball between zero and ten degrees, as opposed to under 10 degrees is 1.979 points! You might be thinking to yourself, “1.979 points per ball in play does not seem like a lot” However, remember that the average points per ball in play for all batted ball types is only 1.525. We get a production bump in FGpts when moving from DB to GB, we should expect a similar bump from GB to LD.

FGpts Values for Low Drives (LD)
Out Single Double Triple Home Run Total Average
FGpts Value -1.00 4.60 7.50 10.30 14.00
Points Scored -2,712 19,812 14,220 1,257 1,274 33,851 3.708
wOBA 0.00 0.90 1.25 1.60 2.00 6,624 0.726
Events 2,712 4,307 1,896 122 91 9,128
SOURCE: Baseball Savant, xStats.org

Huzzah! We see a similar bump in production to what was expected. Let’s run through the other 3 batted ball types real quick.

FGpts Values for High Drives (HD)
Out Single Double Triple Home Run Total Average
FGpts Value -1.00 4.60 7.50 10.30 14.00
Points Scored -2,931 4,770 9,015 1,174 15,932 27,960 4.354
wOBA 0.00 0.90 1.25 1.60 2.00 4,894 0.762
Events 2,931 1,037 1,202 114 1,138 6,422
SOURCE: Baseball Savant, xStats.org
FGpts Values for Fly Ball (FB)
Out Single Double Triple Home Run Total Average
FGpts Value -1.00 4.60 7.50 10.30 14.00
Points Scored -6,133 2,705 3,360 1,082 26,628 27,641 3.012
wOBA 0.00 0.90 1.25 1.60 2.00 5,061 0.552
Events 6,133 588 448 105 1,902 9,176
SOURCE: Baseball Savant, xStats.org
FGpts Values for Pop Ups (PU)
Out Single Double Triple Home Run Total Average
FGpts Value -1.00 4.60 7.50 10.30 14.00
Points Scored -9,880 865 660 93 1,260 (7,003) (0.683)
wOBA 0.00 0.90 1.25 1.60 2.00 474 0.046
Events 9,880 188 88 9 90 10,255
SOURCE: Baseball Savant, xStats.org

Okay, a lot to digest, I know. What we wanted to see was that Fangraphs points was doing a good job of ranking the following categories. Pop-ups, are the worst batted ball type followed closely by dribble balls. After those two, ground balls are worse than fly balls, and low drives are worse than high drives. That is exactly what we see here. It appears, several years after it’s inception, that FGpts is still holding up as a scoring setting which is mimicking reality. To look at this a slightly different way:

Increase in FGpts per point of wOBA
LA Class wOBA – 17 FGpts delta wOBA delta FGpts FGpts/wOBA
0 Dribble Ball 0.167 0.046
10 Ground Ball 0.479 2.025 0.312 1.979 0.0634
19 Low Drive 0.726 3.708 0.247 1.683 0.0681
26 High Drive 0.762 4.354 0.036 0.646 0.1794
39 Fly Ball 0.552 3.012 -0.210 -1.342 0.0639
39+ Pop Up 0.046 0.046 -0.506 -2.966 0.0586
All 0.377 1.525
SOURCE: Baseball Savant, xStats.org

The wOBA increase on batted balls when going from a DB to a GB is .312, which corresponds to the 1.979 increase in FGpts per event we mentioned above. So, for each point of wOBA a hitter gains between these categories, there is an associated gain of roughly .063 points per point of wOBA. If we didn’t want to consider transitioning between batted ball types, we could take a more general view, and notice that on average 1.525 points per batted ball are scored with a wOBA of .377. On average, that would mean that for each point increase of wOBA on balls in play, we would gain roughly .04 FGpts. Hopefully, this is helpful in understanding the different batted ball types based on launch angle and how they correspond to Ottoneu. I ¬†know there’s a lot of information here.

We hoped you liked reading Fangraphs Points Results by Launch Angle by Joe Douglas!

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Joe works at a consulting firm in Pittsburgh. When he isn't working or studying for actuarial exams, he focuses on baseball. He also writes @thepointofpgh. Follow him on twitter @Ottoneutrades

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