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Quantifying Tim Tebow's miracles

Posted by Andrew Mooney  November 25, 2011 12:23 AM

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Week 15 looms large among the games remaining on the Patriots’ schedule –– not because of its playoff implications or a meeting with a heated rival, but because New England fans will get an up-close look at the NFL’s biggest sideshow: the Tim Tebow-led Denver Broncos.

Tebowmania has inspired everything from “Jesus” jerseys to a ubiquitous signature pose. What it hasn’t inspired in anyone who has watched Tebow play is confidence that he can complete a pass 10 yards downfield.

As a traditional NFL quarterback, Tim Tebow looks lost. Take his first two starts this year: unable to make the necessary reads in time, Tebow lingered in the pocket interminably, drawing 14 sacks in 80 dropbacks. His 44.8 completion percentage ranks last in the NFL for quarterbacks with more than 100 passing attempts. His own coach, as justification for overhauling the Broncos’ offensive schemes, admitted “he’d be screwed” in a regular offense.

But Tim Tebow is not a traditional NFL quarterback, so it doesn’t make sense to evaluate him like one. Pure passing statistics won’t tell the whole story. To better assess the respective contributions of Tebow and the quarterback he replaced, Kyle Orton, we’ll use Expected Points Added (EPA), a statistic that records the result of each play –– given down, distance, and yard-line –– and converts it to a point value. (A more thorough explanation can be found here, at advancednflstats.com).

Without applying context to the numbers, the insertion of Tebow has actually hurt the Broncos –– his EPA this season (-13.4) is 13 points lower than that of Orton (-0.3). This includes his contributions on the ground; Tebow’s inadequacies in the passing game have been so pronounced that his overall statistics are still worse than Orton’s, despite also being the team’s second-leading rusher.

Yet inexplicably, the Broncos are 4-1 with Tebow at the helm. In fact, correcting for strength of schedule with Jeff Sagarin’s team ratings, the Broncos would have been expected to win, on average, only 1.9 of Tebow’s five starts. By what sort of heavenly magic has Tebow been able to conjure up those additional 2.1 wins?

Tebow has saved his best for the biggest moments. By examining his Win Probability Added (WPA), which measures the effect of each play on the odds of victory of a player’s team (much the same as EPA, except that it also factors in score and time remaining), we can see that his value has been greater than what his raw numbers indicate. Much of Tebow’s production –– his game-winning drives against the Dolphins and Jets, for example –– have occurred with the game’s result largely in doubt, when individual plays have a larger impact on a team’s chances of victory. As a consequence, his WPA, though still negative, is much higher than his EPA (-0.06) and also exceeds Orton’s WPA (-0.45). So while, on the whole, Tebow has contributed fewer expected points than Orton, the points he has generated have come at the most important times, making up for his otherwise inferior performance.

How long can Tebow’s remarkable stretch continue? As illustrated in the graph below, which plots the EPA and WPA for each season played by all NFL quarterbacks currently in the league, there is a strongly linear relationship between the two metrics. Over the course of a season, players like Tebow, who possess significant disparities between their EPA and WPA, tend to regress toward their expected means along this line, implying that Tebow’s current streak is unsustainable for any extended period of time.

It’s possible that the Broncos keep up their winning ways under Tebow –– he’ll just need to play a lot better. If he continues to rely on a series of coordinated miracles to bail him out, his record won’t look so spectacular in the long run.

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Thus far, Tebow has certainly exhibited a knack for excelling in crunch time, but to overlook his flaws and simply anoint him as a “winner” is a drastic oversimplification. Excepting divine intervention, nothing related to Tim Tebow bears responsibility for the crucial plays that allowed for his late-game heroics on multiple occasions: the onside kick recovery in Week 7 against the Dolphins, or Andre Goodman’s pick-six against the Jets.

NFL defenses are simply too savvy to be bested by a gimmicky, one-dimensional offense like the read option for long (anyone seen the Wildcat lately?). If Tebow hopes to remain the Broncos' quarterback of the future, he’d better start watching some old Elway game film. Pretty soon, his guardian angel is going to need a vacation.

This blog is not written or edited by Boston.com or the Boston Globe.
The author is solely responsible for the content.

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Stats Driven is powered by David Sabino, who over the last two decades has been a source of statistical analysis on the pages of Sports Illustrated, New York Times, and Chicago Tribune. David has written about all seven recent Boston-area championships for Sports Illustrated Presents commemorative issues, was the creator of such long time features as SI’s Player Value Ranking, NBA Player Rating and long running fantasy football and baseball columns.

He has also authored or made contributions to many books, including the Sports Illustrated’s 100 Fenway: A Fascinating First Century.

Now living in Marblehead, he’s focusing his attention on the Boston sports scene, specifically delving into the numbers affecting the Red Sox, Patriots, Celtics and Bruins, with the goal of informing and entertaining real fans. You can follow him on Twitter at @SabinoSports.

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