During the regular season, Jimmy Garoppolo had 143 pass plays on third down. On 13 of those pass plays, he took a sack. On the other 130 third down pass plays, Garoppolo gained a first down on exactly half of them. On Saturday, commenter LightsOut85 pointed out that he thought Garoppolo’s great third down performance was “more an indicator of SF’s offensive scheme (namely YAC) than his passing ability.”

Is that true? I decided to investigate. Of Garoppolo’s 130 third down pass plays that were not sacks:

• • 41 of them (31.5%) were thrown at or beyond the first down marker (i.e., past the sticks) and completed for a first down.
  • 30 of them (23.1%) were thrown past the sticks but fell incomplete.
  • 24 of them (18.5%) were thrown short of the sticks but still picked up a first down (this is the category LightsOut85 was focused on).
  • 35 of them (26.9%) were thrown short of the sticks and did not pick up a first down.

The graph below shows each of his 130 pass attempts. It is color-coded to make it easier to read, but let’s explain.  The X-Axis shows the distance — i.e., it was 3rd-and-X.  The Y-Axis shows the amount of air yards for the throw.  For example, at the top right, you will see a 3rd-and-16 pass that went for 41 air yards, which was one of the more memorable plays of the 49ers season.

If the pass was thrown at or beyond the sticks, the bubble is blue.  If it was converted for a first down, the dot is fully colored in blue; if it was not, it is a white bubble with a blue outline.  If the pass was thrown short of the sticks, the bubble is red.  If it was converted for a first down, the dot is fully colored in red; if it was not, it is a white bubble with a red outline.

The real outlier here is in the 3rd-and-6 to 3rd-and-9 range.  Garoppolo had 43 pass plays in this situation: on 22 of those, the ball went to the sticks or beyond, and it was completed 14 times.  But on 21 of these, Garoppolo threw a pass short of the sticks, and he picked up a first down on 15 of them!

Now this is obviously a case of using multiple endpoints – you can see from the graph that the 6-to-9 range was a real outlier here, and Garoppolo had a lot of passes short of the sticks on 3rd-and-5 and 3rd-and-10 that were shy of the sticks and did not gain a first down.  But the general trend here is noteworthy: he does in fact throw a lot of passes on third down that are short of the sticks and still gain a first down.

In fact, Garoppolo picked up a first down on 41% of his overall third down passes that were short of the sticks. That was the highest rate in the NFL.

Now, throwing short of the sticks is not necessarily a bad thing or even a real criticism of a quarterback. But on average, it probably says less about a quarterback’s ability when the first down is completed shy of the sticks and the receiver then gains the first down.

Finally, here’s a look at Garoppolo on all passes between 3rd-and-5 and 3rd-and-10. Here’s how to read the chart below. He had 71 pass attempts in these situations, and 34 of them — 48% — were short of the sticks. That’s a high amount, although not highest in the league (Keenum, Brees, Flacco, and Rudolph were all much higher). However, he converted 53% of his passes in these situations that were SOS — short of the sticks — into first downs, which *was* the highest in the league. That’s really where Garoppolo stands out: over half of his throws on 3rd-and-5 to 3rd-and-10 were short of the sticks and still picked up a first down, which is very unusual. Finally, he converted 59% of his attempts in these situations where the throw was AoBS — At or Beyond the Sticks — into first downs.