I just returned from my annual geek-out vacation to the MIT Sloan Sports Analytics Conference in Boston. If you haven’t been, its a two-day series of panels and discussions on my two favorite things: Sports and Data.
Here at Fantasyomatic.com, our goal is to bring you new ways to look at data to give you an edge in your fantasy football leagues. So I wrote up some findings to sure with you based on panels attended at this year’s conference.
I attended a sessions presented by ESPN called “Total QBR: What ESPN Analytics Learned“. ESPN Journalist Peter Keating was joined by four other ESPN Stats staffers to explain why ESPN created the “Total QBR” to improve upon the NFL Passer Rating.
In addition to learning compelling details about the new rating, I learned one important fact:
Total QBR (0-100) and a new metric called “Clutch Weighted EPA” predict fantasy value better than traditional stats or fantasy stats
In fact, in 2010 and 2011, Total QBR (QBR for short) even correlated to Fantasy QB production significantly more than NFL Passer Rating. Keating wrote a comprehensive article about this last fall on ESPN Insider and you should really read it.
Sure, you never heard much about looking at passer ratings for fantasy purposes, but with a correlation of .64 (vs .55 for Passer Rating), QBR enters the conversation as a noteworthy metric for the first time this offseason.
To understand QBR, lets first take a look at the old NFL Passer Rating and why ESPN chose to revamp it with QBR.
NFL Passer Rating
The NFL rates its passers for statistical purposes against a fixed performance standard based on statistical achievements of all qualified pro passers since 1960. The current system, which was adopted in 1973 (an hasn’t changed since) provides a means of comparing passing performances from one season to the next.
The system itself is older than every active NFL QB and only considers 4 variables:
• Percentage of completions per attempt
• Average yards gained per attempt
• Percentage of touchdown passes per attempt
• Percentage of interceptions per attempt
On first look, you might think these are perfect metrics for fantasy production since long yardage and TDs score points and INTs penalize your fantasy QBs.
The average standard, is 1.000. The bottom is .000. To earn a 2.000 rating, a passer must perform at exceptional levels, i.e., 70 percent in completions, 10 percent in touchdowns, 1.5 percent in interceptions, and 11 yards average gain per pass attempt. The maximum a passer can receive in any category is 2.375.
This system is fine for determining individual successful plays, but it lacks certain metrics that could help you better reveal the long term value of a QB in a fantasy context.
The NFL Passer Rating needed an update. As a tool for evaluating quarterbacks for all that they do, the NFL Passer Rating was missing too much and missed out on some metrics that make a “real life” QB a valuable fantasy QB.
Enter Total QBR
Upon design, ESPN wanted to create a quarterback rating that could be used as a tool for identifying a better quarterback. Quarterbacks get expected points through completions and incompletions, interceptions, interception returns, sacks, fumbles, fumble recoveries, scrambles, designed rushes, defensive pass interference penalties.
It accounts for the game situation of every play. It’s what QBs do with their arm and their feet. It’s when they do it and how that relates to their team’s chances of scoring, and therefore your fantasy team’s scoring potential.
The fantasy advantage to QBR is that is takes into account the following fantasy relevant factors:
– When a QB creates more opportunities for himself (thus more chance for fantasy production)
– When a QB makes good passing decisions (thus limiting interception penalty liability)
– When a QB was productive as a runner (thus scoring points through rushing yards and scores)
– When a QB fumbles the ball (thus limiting fumble penalty liability)
– When a QB throws passes that are dropped (thus squandering potential points)
Considering every one of these variables contributes to the single game and full season value of your fantasy QB, the QBR serves as a better indicator of fantasy QB value. This will help you see how much interceptions, sacks, and fumbles hurt a QB and how completions and scrambles and designed rushes add to a QB’s fantasy value.
Clutch Weighted EPA
The Clutch Index or Clutch Weight might be familiar for those who work with baseball analytics and are a measure of how important any play is towards changing the winning percentage of the game.
This Clutch Index reflects how much pressure a player may feel on the play. For example, imagine a team down 4 with 30 seconds to go in the game. In one case, it is 3rd and goal from the 3 yard line. In the second case, it is 3rd and 10 from midfield. In the first case, it is a high pressure situation. The team can win with the right play call, the right block, or the right pass, but they can also lose the game with the wrong call, block, or pass or bad decision.
EPA represents “Expected points added” that occur as a result of an action play. These could be positive or negative. There are four components that contribute to EPA:
• Pass EPA: Clutch-weighted “expected points added” through pass attempts by the QB.
• Run EPA: Clutch-weighted “expected points added” through scrambles, designed rushes and fumbles/fumble returns on running plays by the QB.
• Sack EPA: Clutch-weighted “expected points added” through sacks and fumbles/fumble returns on passing plays by the QB.
• Penalty EPA: Clutch-weighted “expected points added” on penalties by the QB.
Both of these metrics together combine for the “Clutch Weighted EPA” and factor into a higher QBR for each QB. It should be noted, however, that Clutch Index doesn’t benefit QBs that score fantasy points in “garbage time” against prevent defenses. So in this one regard, the QBR might not be the best way for you to find a good garbage QB. You can always just look at a QB on a team with a horrible defense if thats your goal.
So, QBR is meant to correlate to offense, moving the ball downfield (passing yard fantasy points), turning good field position into points (TD fantasy points), avoiding giving it back to the defense (interception or fumble fantasy point deductions). Good offensive performance contributes to fantasy scoring. To the degree that a good offense correlates to winning in fantasy football, QBR should be helpful.
Using QBR for your 2012 Fantasy QB
Keating’s article points out a study that finds that the correlation between 2010 passer rating and 2011 fantasy points is 0.55. And the correlation between 2010 fantasy points and 2011 fantasy points is a stronger: 0.62.
But Keating’s analysis shows that QBR beat them all, with a correlation of 0.64. To speak to the the statement that “Total QBR and “Clutch Weighted EPA” predict fantasy performance best”, QBR’s estimate of the total points added by quarterbacks to their teams (CWE), resulted in the single best predictor of fantasy scoring of all evaluated with a correlation of 0.67.
Those of you that play fantasy baseball know that a pitcher’s current ERA is a better predictor of his future win-loss record than his current win-loss record and similarly, QBR and CWE predict fantasy scoring better than past years fantasy points do.
The study also looked at how 2009 stats translated into 2010 fantasy points, and among the correlations, QBR and CWE are still stronger than passer rating, TDs, yards, yards per game or attempts.
The thesis here is that a quarterback’s rushes, sacks, fumbles and yards after catch are moderately related to the fantasy points he racks up the following season. Traditional passing stats (and therefore, Passer Rating) account for none of them; QBR includes all of them.
The QBR Conclusion
Since QBR tracks components of a quarterback’s game that persist into future fantasy scoring but that other metrics aren’t capturing, it stands to reason that the difference between QBR and traditional stats will predict value buys in fantasy leagues.
For example, if two quarterbacks have similar passer ratings but very different QBRs, the player with the better QBR “should” score more fantasy points next season. But fantasy owners used to watching conventional stats aren’t likely to notice this.
As stated in the “Fantasy Sports Analytics” panel at the SSAC: Analytics in fantasy sports isn’t about being perfect, its about being better than your league mates.
The panel stated this best: “If a bear is chasing you and your friends in the woods, you don’t have to be able to outrun a bear, you just need to outrun you friends”.
The connection isn’t “absolute”, but it’s there. QBR points to future fantasy points. And QBR relative to other stats points to fantasy breakouts and declines. Armed with this data, you can outrun the bear.
2011 QBR Ratings
With this strategy in mind, here are last year’s QBR ratings to help you start prospecting your 2012 fantasy team QB: