This stat dive began with a simple question: What’s wrong with Trevone Boykin's QBR?

The TCU superstar enjoyed a phenomenal breakthrough last year and is now being held up as a Heisman contender for 2015. Yet he finished with a less-than-elite QBR of 72.5 for the year, good for No. 22 in FBS.

Instead of blaming the typically effective metric, let’s take a closer look at one area where Boykin has room to improve in his senior season: third downs.

TCU’s offense ran 198 plays on third down last season. Boykin passed or rushed on 149 of those snaps. He converted first downs on 59 of those plays, a success rate of nearly 40 percent.

He was a 55 percent passer on third downs last season, ranking 60th in FBS, with nine touchdowns and four turnovers. When he connected, TCU moved the ball -- Boykin averaged 13.3 yards per completion on third down. Yet third downs are judged not by the yards you gain, but by the yards you need.

And when Boykin threw the ball on third down, he moved the chains 40 percent of the time.

Surprisingly, Boykin's success rate on conversions was slightly worse (37 percent) when he decided to take off and run on third down.

Those third-down issues were magnified at times in the red zone: TCU scored touchdowns on 47 percent of third-down plays inside the 20, a rate that ranked 93rd in FBS. We saw these issues play out most alarmingly at West Virginia, where Boykin completed 3 of 9 passes for 22 yards on third down. That game nearly derailed the Horned Frogs’ run to a share of the Big 12 title.

So why were third downs problematic for Boykin? Well, TCU did face an average distance of 7.5 yards to gain on third downs last season. That’s a problem, and an average that ranked 97th in FBS. The Frogs were forced into passing downs a lot: two-thirds of all TCU third downs were third-and-5 or longer.

Boykin fared OK but not great on those passing downs, completing 56 percent of his passes at a rate of 7.2 yards per attempt, only barely above the national average. (Oregon’s Marcus Mariota, by comparison, averaged 11.3 YPA.)

And yet, despite these trends, TCU still averaged more than 46 points per game and broke countless school records in the first year of a new offensive scheme. In a sense, the third-down troubles make all that high-speed production even more admirable.

There’s an easy answer, of course, for how to fix this: another year of practice for an offense that returns practically everybody.

Boykin will probably be even better protected by his line and has built up stronger rapports with Josh Doctson, Kolby Listenbee and his receivers. Aaron Green and the backs can do a better job of avoiding all those third-and-longs by keeping the offense on schedule on the ground.

Yes, defenses will likely do a better job of spying on Boykin to limit his scrambling opportunities this year, and should have better answers for attacking TCU’s offense. That promises to make his decision-making and precision inside and out of the pocket even more important in 2015 -- especially on third downs.