Is Tebow the reason the Broncos are winning? Every third news item or blog post I come across seems to be pulling its collective hair out, pondering the Broncos' 5-1 run. He's a winner! No, he's no good! He can't throw! But he runs! He doesn't turn the ball over! He doesn't take sacks! He puts his team in a hole! He's clutch! On one hand this, on the other hand that. If only their were a single number, tuned precisely to tell us how much a player contributes to his team's fortunes...That would settle the question.
Fortunately, that's what Win Probability Added (WPA) does. As a starter in 2011, Tebow has a -0.18 WPA. Suppose the football gods gave us a test with the question, On net, has Tebow helped or hurt the Broncos' chances of winning since he became the starter? Show your work. I'd write down: Hurt. -0.18 WPA. And I'd be marked correct.
We could end the discussion right there if we wanted, but that's no fun.
Tebow and the entire Bronco team had a singularly terrible game against Detroit in their only loss during Tebow's stretch as the starter. Tebow himself posted a -0.22 WPA that week. Setting that aside, his total WPA in his wins comes to +0.04 wins, mildly positive. In those same games his EPA is +8.2 points, also mildly positive.
The big reason Denver is winning is defense, RB play, and special teams. However, because of Tebow's unconventional style and scheme, some of the success of the Denver running backs could rightfully be attributed to him. Plus, he may be the perfect fit for a team built around defense. He doesn't turn the ball over or take sacks, and he can use the clock by playing keep-away with his running. But keep in mind, except for his possible effect on RB success, WPA already captures these considerations.
But even in the win yesterday, he struggled almost all afternoon. He completed 50% of his passes. He had a 36% success rate. Down by 3 late in the 4th quarter, he couldn't find the end zone, and the Broncos had to settle for a tying FG, giving the ball back to SD with 1:38 to play. In overtime, Tebow struggled again. Only on his third possession, which was possible only because SD missed a long FG attempt, was he able to move the ball. Tebow had 16 yards rushing on the dirve, but the big play was Willis McGahee 24-yd run. For the day, Tebow accumulated -0.23 WPA, which was actually slightly worse than his loss against Detroit.
The best case you can make for Tebow is that, in his wins, he's usually helped his team slightly more than he has hurt it. I'm not sure if that's a fair assessment because if you only look at any QB's winning games, you'd almost always find that he's helped more than hurt.
But don't get me wrong. I enjoy watching Tebow play because I love the unconventional offense and I love the innovation. I love that John Fox fits his scheme to his personnel and not the other way around. And in an age when every minor successful play results in some ridiculous showboating, finger-wagging dance, Tebow's attitude is refreshing.