Total quarterback rating

Total Quarterback Rating (abbreviated as Total QBR or simply QBR) is a measure of the performance of quarterbacks or any other passers in American football developed by the American sports network ESPN in 2011. The network claims it is a more meaningful alternative to the older NFL passer rating, which remains the official NFL measure of quarterback performance.

Summary of computation
According to ESPN, QBR was developed to measure the degree to which a quarterback contributed to scoring points for the team, and also to a win by the team. For example, completing a pass to earn a first down at the quarterback's own 20-yard-line with 30 seconds left in the game is unlikely to lead to any points for his team, but if they are already leading it increases the probability of winning, as it usually enables the leading team to run out the clock. This second criterion is quantified using a "win probability" function which ESPN developed by analyzing data for each play of NFL games over the previous decade.

The computation requires an examination of each play in which the quarterback was involved. For each play, the change in the expected value of the points scored by the two teams is determined along with the maximum possible change in points for each team. The net points gained by the offense on the play are divided between the players involved in the play based on how much each contributed to the points gained or lost. For example, on a play where the quarterback immediately hands the ball off to a running back after the snap, the quarterback's contribution is negligible. On passing plays the quarterback is likely to have a major contribution, along with the blockers and the receiver. The resulting value is compared the maximum possible net point gain, and this comparison leads to a "net points percentage" value between 0 and 100 for the quarterback on each play which roughly represents the percentage of the possible point gain that the quarterback produced. This value is transformed so that a value of 50 represents the average net point gain of an NFL quarterback on the play.

The win probability function is then used to compute a "clutch index" for each play ranging from 0.3 to 3.0, with higher values corresponding to plays that have a greater influence on winning or losing the game. The QBR is obtained by taking the weighted average of the "points gained percentage" for each play, with each play having a weight equal to its clutch index. Thus the QBR has a range from 0 to 100 with 50 being considered average.

Comparison to NFL Passer Rating
The calculation of the NFL passer rating is much simpler than the QBR, as it depends only on aggregate statistics rather than an analysis of each play a quarterback is involved in. Passer rating is calculated using each quarterback's completion percentage, passing yardage, touchdowns and interceptions, and has a maximum value of 158.3 and minimum value 0, with 80 being considered average.

Reception
Unlike the NFL passer rating, ESPN has not yet been forthcoming on the exact specific formulas and procedures to calculate QBR. The proprietary, complex methodology spans some 10,000 lines of code. In an interview with San Diego's XX Sports Radio, San Diego Chargers quarterback Philip Rivers seemed baffled by the ratings, which put him ninth overall in its metrics for the 2010 season, saying "I still don't get it. I think it's more complicated now".

In an op-ed piece published by Deadspin, they opine that the clutch index component of the QBR "looks like a weirdly applied version of baseball's leverage metric and which, tellingly, is the sort of mindless branding you get when the network of 'Who's Now' starts dicking around with numbers.". And The Baltimore Sun's Matt Vensel wrote, "I can’t say the new rating system ... is any better. And that's because I don’t really understand or care to understand how Total Quarterback Rating works".

Michael David Smith of Profootballtalk.com explained the major drawback of QBR: One of the aspects of Total QBR that could be both a strength and a drawback is that it considers data that the average fan doesn’t have access to, like how far a pass travels in the air, and whether the quarterback was under pressure when he threw it ... it means fans can't see for themselves exactly where Total QBR comes from — fans just have to trust that the distance the ball traveled was correctly measured, and how much pressure the quarterback felt on the play was correctly assessed ... If ESPN is committed to this stat and is able to clearly and concisely explain it on the Worldwide Leader’s NFL broadcasts, then fans will quickly become familiar with it and it will soon become a staple of how we talk about quarterbacks. On the other hand, if the stat comes across as too convoluted — or if it doesn’t really seem like much of an improvement on the current passer rating — then this will all feel like a rather pointless exercise.

On the other side, noted football author and researcher Brian Burke of Advanced NFL Stats opined that QBR was superior to the traditional passer rating. The main advantages, in his opinion, are QBR's accounting for many more events in quarterback play than the old rating, and the fact that it avoids the double-counting that plagues the official NFL passer rating. He did however lament the proprietary nature of the statistic, and predicted it would not become widely used so long as its precise computation details were kept secret (e.g. it is unlikely that CBS, Fox, NBC, and other competing media outlets would want to heavily promote something that is proprietary to ESPN).

Further controversy erupted when the Total QBR system gave the Denver Broncos' Tim Tebow a higher rating than the Green Bay Packers' Aaron Rodgers in their respective Week 5 contests in 2011. Noting that Rodgers completed 26 of 39 passes for 396 yards and two touchdowns in a win over the Atlanta Falcons, while Tebow completed four of 10 passes for 79 yards and a touchdown, and six rushes for 38 yards and a touchdown, in a loss to the San Diego Chargers, Mike Florio of Profootballtalk.com wrote that he'll "continue to ignore ESPN’s Total QBR stat." Rodgers himself was surprised: "I saw the [QBR stats] and chuckled to myself. I played a full game, [Tebow] played the half. He completed four passes, I completed 26. I think it incorporates QB runs as well ... The weighting of it doesn't make a whole lot of sense." ESPN's Stats and Information Group explained that Tebow's higher rating was the result of him staging a partial comeback, taking no sacks, and having positive rushing yards and a rushing touchdown, among other factors. However, Doug Farrar of Yahoo! Sports wrote that the QBR system lacks a minimum performance frequency floor that players must meet before they can be rated, and thus it essentially penalizes Rodgers because he played throughout the entire game, while rewarding Tebow because he came off the bench in the second half in an attempt to stage a comeback.