NFL Analysis: Should the Falcons Have Tried a QB Sneak vs. Saints?

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In the NO-ATL game Sunday, ATL went for a risky 4th down and 1 conversion attempt in OT with just inches to go. They elected for a RB dive play rather than a QB sneak. (By dive play, I just mean a straight RB handoff directly between the tackles.) But all '4th and 1' situations are not equal--from 1.5 yards down to an inch to go.

QB sneaks seem more successful on inches-to-go situations than RB dives. We'd like to know if the data back this up. Unfortunately, the play descriptions don't note how long the 'and 1' is, whether it's a long yard or just inches. We'd expect to see more QB sneaks on the shorter distances and more RB dives on the longer distances, which bias the numbers because longer to go distances would naturally be tougher to convert. Still, we may be able to draw some inferences.

The table below lists the success rates for 3rd and 4th down runs with 1 yard to go. It breaks out plays by QBs, RBs, and FBs. QB scrambles on pass plays have been removed. Kneel downs and spikes are also removed. Plays inside the 10 yd line are removed due to field compression effects.

Conversion success rates on 1-yd to go runs (%)

Position3rd Down4th DownFB7770QB8782RB6866Total7272

The next table lists the frequency of each type of play by down and position.

Frequency of play type on 1-yd to go runs (%)

Position3rd Down4th DownFB108QB1631RB7460

At first glance, it appears QB sneaks are underused and RB dives are overused. It's also notable that the QB sneak is used significantly more often on 4th down than on 3rd down. I suspect this is from the selection bias--4th down attempts are more common on shorter "1 yard" to-go distances because teams would tend to kick more on the longer to-go situations. 3rd down doesn't suffer the same biases, except perhaps that teams might choose to pass on "longer yards" and run on inches to go. Consequently, we can't draw any definitive conclusions about the relative effectiveness of the tactics.

Or can we?

Data from 2-yd to-go distances can help clarify the issue. The one thing we know about 2-yds to go is that it's always longer than 1-yd to go. I realize how simplistic that sounds, but it's an important point. Note below that QB sneaks on 2-yds to go are just as successful as RB dives on 1-yd to go!

Conversion Success Rates on 2-yd to go runs (%)

Position3rd Down4th DownFB6050QB8062RB5856Total6057

Actually, 2-yd QB sneaks are far more successful than 1-yd RB dives on 3rd down and slightly less successful than 1-yd RB dives on 4th down. Taken overall, this suggests that the QB sneak is an underused tactic as far out as 2 yds to go. It also explains why running on short yardage is more successful than passing--it's the QB sneaks that make the difference.

Note that there is still bias in the data. Teams with strong lines or quick, strong QBs will tend to trust the sneak, and they're also the teams that would be most successful doing so. But the bias runs both ways. Teams with powerful RBs would call their number more often and be more successful doing it. I think we can infer from this data that, whatever coaches believe about the general potential for success of the two tactics, they underestimate the QB sneak and rely too much on the RB dive.

My thanks to commenter Frank for the insight.