Column by Nicholas Higgins
One graphic that sometimes pops up late in NFL games is "number of game-winning drives," which is implied to be a metric of clutch quarterback ability. However, this figure is meaningless out of context, and raises a number of questions. How many opportunities did the quarterback have to lead a game-winning drive? If the quarterback leads his team on a drive to take the lead with one minute left, and then his defense subsequently surrenders a touchdown, shouldn’t he still get credit for that drive? What if the quarterback leads the team on a long drive to the 5-yard line, only for the kicker to miss the game-winning, chip-shot field goal as time expires?
The purpose of the Adjusted Comeback Efficiency (ACE) Rating is to provide a comprehensive figure for measuring a quarterback’s performance in potential game-winning or game-tying situations. First, the methodology of the ACE rating will be briefly explained. This is followed by an analysis of the results. At the end, the methodology calculations are shown in greater detail for those that are interested.
Basic Methodology
The ACE rating compares a quarterback's outcome in a given situation to the expected or average outcome in that situation. Adjustments were made for four factors: starting field position, time remaining in game, deficit (how many points behind), and outcome (no score, field goal attempt, touchdown). For example:
Quarterback A: after an interception return, he starts at his opponent's 5-yard line down by one point with two minutes to go
Quarterback B: after a kickoff, he starts at his own 20-yard line down by 8 points with 30 seconds to go
Quarterback A has a much easier scenario than Quarterback B. Therefore, the ACE rating gives more credit to Quarterback B for a successful comeback than Quarterback A, and penalizes Quarterback B less than Quarterback A for failure. A touchdown is worth more credit than a field goal in most situations (one exception: overtime). If the offense attempts a field goal, it is irrelevant for the ACE rating whether the kicker makes it or misses it. Instead, the quarterback gets credit based on the average success rate for that distance of field goal, such that a short field goal attempt receives more credit than a long field goal attempt.
There are some more adjustments, but the concept is simple: The ACE rating calculates how efficient a quarterback is in potential comeback situations, taking into account the level of difficulty of the situation.
Quarterback Rankings
This list includes all quarterbacks with at least 30 qualifying drives from 1998 to 2009 (including playoffs). For some quarterbacks, this means that this data set only captures part of their career (e.g. Dan Marino at No. 43 from the last two years of his career, 1998-99). At the bottom, I have listed some noteworthy young quarterbacks that have not yet reached the drive threshold, although caution should be exercised with such thin data. For each player, we also provide the NFL's QB rating for comparison purposes.
Rank QB ACE Drives CBs CB% QBR QBR Rank Rank Diff
1 E.Manning 1.55 66 28 42.4% 79.2 32 31
One graphic that sometimes pops up late in NFL games is "number of game-winning drives," which is implied to be a metric of clutch quarterback ability. However, this figure is meaningless out of context, and raises a number of questions. How many opportunities did the quarterback have to lead a game-winning drive? If the quarterback leads his team on a drive to take the lead with one minute left, and then his defense subsequently surrenders a touchdown, shouldn’t he still get credit for that drive? What if the quarterback leads the team on a long drive to the 5-yard line, only for the kicker to miss the game-winning, chip-shot field goal as time expires?
The purpose of the Adjusted Comeback Efficiency (ACE) Rating is to provide a comprehensive figure for measuring a quarterback’s performance in potential game-winning or game-tying situations. First, the methodology of the ACE rating will be briefly explained. This is followed by an analysis of the results. At the end, the methodology calculations are shown in greater detail for those that are interested.
Basic Methodology
The ACE rating compares a quarterback's outcome in a given situation to the expected or average outcome in that situation. Adjustments were made for four factors: starting field position, time remaining in game, deficit (how many points behind), and outcome (no score, field goal attempt, touchdown). For example:
Quarterback A: after an interception return, he starts at his opponent's 5-yard line down by one point with two minutes to go
Quarterback B: after a kickoff, he starts at his own 20-yard line down by 8 points with 30 seconds to go
Quarterback A has a much easier scenario than Quarterback B. Therefore, the ACE rating gives more credit to Quarterback B for a successful comeback than Quarterback A, and penalizes Quarterback B less than Quarterback A for failure. A touchdown is worth more credit than a field goal in most situations (one exception: overtime). If the offense attempts a field goal, it is irrelevant for the ACE rating whether the kicker makes it or misses it. Instead, the quarterback gets credit based on the average success rate for that distance of field goal, such that a short field goal attempt receives more credit than a long field goal attempt.
There are some more adjustments, but the concept is simple: The ACE rating calculates how efficient a quarterback is in potential comeback situations, taking into account the level of difficulty of the situation.
Quarterback Rankings
This list includes all quarterbacks with at least 30 qualifying drives from 1998 to 2009 (including playoffs). For some quarterbacks, this means that this data set only captures part of their career (e.g. Dan Marino at No. 43 from the last two years of his career, 1998-99). At the bottom, I have listed some noteworthy young quarterbacks that have not yet reached the drive threshold, although caution should be exercised with such thin data. For each player, we also provide the NFL's QB rating for comparison purposes.
Rank QB ACE Drives CBs CB% QBR QBR Rank Rank Diff
1 E.Manning 1.55 66 28 42.4% 79.2 32 31
2 B.Roethlisberger 1.44 78 34 43.6% 91.7 8 6
3 P.Manning 1.40 145 62 42.8% 95.2 4 1
4 P.Rivers 1.36 51 22 43.1% 95.8 2 -2
5 A.Rodgers 1.33 32 13 40.6% 97.2 1 -4
6 M.Schaub 1.33 38 14 36.8% 91.3 9 3
7 J.Cutler 1.32 55 21 38.2% 83.8 20 13
8 T.Green 1.31 105 37 35.2% 86.0 16 8
9 T.Romo 1.31 45 15 33.3% 95.6 3 -6
10 D.Brees 1.31 88 36 40.9% 91.9 7 -3
11 C.Palmer 1.30 76 27 35.5% 87.9 12 1
12 J.Plummer 1.27 108 39 36.1% 74.7 49 37
13 J.Delhomme 1.25 90 32 35.6% 82.1 27 14
14 T.Brady 1.24 85 38 44.7% 93.3 6 -8
15 R.Gannon 1.21 83 27 32.5% 89.8 11 -4
16 D.Culpepper 1.19 85 25 29.4% 87.8 13 -3
17 J.Garcia 1.17 107 35 32.7% 87.5 14 -3
18 A.Brooks 1.12 81 29 35.8% 78.5 36 18
19 V.Testaverde 1.10 70 23 32.9% 78.6 35 16
20 M.Hasselbeck 1.09 101 33 32.7% 83.3 23 3
Rank QB ACE Drives CBs CB% QBR QBR Rank Rank Diff
21 D.Flutie 1.08 66 22 33.3% 78.7 33 12
22 M.Cassel 1.07 34 11 32.4% 79.6 30 8
23 S.McNair 1.06 107 32 29.9% 83.8 20 -3
24 C.Batch 1.05 38 13 34.2% 77.9 38 14
25 D.Garrard 1.04 58 17 29.3% 84.9 19 -6
26 G.Frerotte 1.04 40 11 27.5% 74.6 50 24
27 K.Warner 1.02 95 23 24.2% 93.7 5 -22
28 J.Fiedler 1.02 52 15 28.8% 77.1 39 11
29 C.Pennington 1.01 69 18 26.1% 90.1 10 -19
30 C.Chandler 1.01 36 11 30.6% 80.6 29 -1
31 K.Collins 1.00 124 36 29% 75.7 44 13
32 D.Bledsoe 0.99 125 33 26.4% 78.7 33 1
33 M.Vick 0.97 62 17 27.4% 75.9 43 10
34 M.Bulger 0.96 77 24 31.2% 82.4 25 -9
35 T.Banks 0.96 44 11 25% 73.0 51 16
36 B.Leftwich 0.95 47 14 29.8% 79.6 30 -6
37 M.Brunell 0.94 98 27 27.6% 83.4 22 -15
38 D.Marino 0.94 32 9 28.1% 74.9 48 10
39 D.McNabb 0.94 129 38 29.5% 86.5 15 -24
40 B.Favre 0.93 187 57 30.5% 85.3 18 -22
Rank QB ACE Drives CBs CB% QBR QBR Rank Rank Diff
41 K.Orton 0.92 38 12 31.6% 76.9 40 -1
42 T.Couch 0.92 63 17 27.0% 75.1 47 5
43 B.Johnson 0.91 110 28 25.5% 81.9 28 -15
44 J.Kitna 0.88 107 26 24.3% 76.6 42 -2
45 T.Maddox 0.87 43 11 25.6% 76.7 41 -4
46 B.Griese 0.85 84 22 26.2% 82.7 24 -22
47 R.Grossman 0.84 35 9 25.7% 69.5 58 11
48 D.Carr 0.83 58 18 31.0% 75.2 46 -2
49 S.Beuerlein 0.81 52 11 21.2% 85.6 17 -32
50 J.P.Losman 0.80 34 8 23.5% 75.6 45 -5
51 D.Anderson 0.76 36 8 22.2% 69.7 56 5
52 Q.Carter 0.76 34 8 23.5% 71.7 54 2
53 E.Grbac 0.73 52 11 21.2% 78.2 37 -16
54 J.Campbell 0.72 54 12 22.2% 82.3 26 -28
55 A.Feeley 0.70 33 8 24.2% 69.6 57 2
56 J.Harbaugh 0.70 36 8 22.2% 72.2 53 -3
57 K.Boller 0.66 42 10 23.8% 70.6 55 -2
58 J.Harrington 0.60 50 11 22.0% 69.4 59 1
59 T.Dilfer 0.56 62 10 16.1% 72.8 52 -7
60 A.Smith 0.55 34 6 17.6% 69.2 60 0
Rank QB ACE Drives CBs CB% QBR QBR Rank Rank Diff
X NFL AVERAGE 1.00 5527 1617 29.3% 81.2 X X
X J.Flacco 1.31 26 10 38.5% 84.9 X X
X C.Henne 1.10 17 5 29.4% 75.2 X X
X M.Ryan 1.77 19 10 52.6% 84.3 X X
X M.Sanchez 1.04 12 3 25.0% 63.9 X X
X V.Young 1.15 29 12 41.4% 72.3 X
Note that the league average is exactly 1.00. A comeback is defined as a successful drive (tie the game or take the lead if trailing; take the lead if the game is tied). CB% is comebacks divided by drives. QBR is QB Rating, QBR Rank is their rank by QB Rating, and Rank Difference is the ACE Rating rank minus the QB Rating rank.
The rankings largely conform to what one would expect: Philip Rivers is a great quarterback no matter the situation, and Joey Harrington is not. The notable cases are when a player’s clutch performance (ACE rating ranking) differs greatly from their overall performance (QB Rating ranking). Eli Manning stands out with the top ACE rating in spite of his below-average QB rating. Eli also has a Super Bowl ring -- in fact, the last four Super Bowls have been won by the players with the top three ACE ratings, and Peyton may make it five in a row. The relationship between ACE rating and Super Bowl success will be analyzed further later on in this column.
Jake "the Snake" Plummer has an even larger differential than Eli Manning, matching Plummer’s reputation as a clutch (but mediocre) quarterback. Another Jake (Delhomme) is a surprising player to see ranked 13th, although perhaps this helps explain how an average quarterback reached a Super Bowl in 2003 and the NFC Championship Game in 2005. Bears fans probably would not expect Jay Cutler to finish in the top 10, but should be happy to learn that their franchise quarterback has consistently had an above-average ACE rating every season (even 2009!). It is still early in their careers, but Aaron Rodgers (fifth) and Matt Schaub (sixth) have both had very promising starts.
Among active players, the quarterback with the biggest negative differential between his ACE rating and QB rating is Jason Campbell. He has an average QB rating, but his terrible ACE rating (0.72, 54th) places him in dubious company, including Quincy Carter, Elvis Grbac, and A.J. Feeley. After Campbell, the players with the largest negative differentials are two superstars with reputations for big mistakes in big moments: Donovan McNabb and Brett Favre. McNabb (0.94, 39th) and Favre (0.93, 40th) both have ACE ratings that confirm their below-average performance in clutch situations. The peak of Favre's career (1995-97) is cut off by the 1998 start date for the our data, but with by far the most comeback opportunities (187) of anyone on the list, there are no issues with data credibility for Favre (his personal credibility is a separate debate).
There is one big-name "choker" quarterback whose reputation is cleared by his ACE rating: Tony Romo. While Romo has a lower ACE rating than QB rating, his ACE rank (ninth) is quite respectable and only looks poor in comparison to his superb QB rating rank (third).
There are two other particularly interesting players whose ACE ratings are lower than their QB ratings: Kurt Warner and Tom Brady.
Warner is fifth in QB rating over the past dozen years, but 27th in ACE rating. Warner has had a very unusual career, however, with higher highs and lower lows than the typical player. He had an above-average ACE rating in all of his six best seasons (1999-2001, 2007-09), and he has been fantastic in the playoffs (2.29 ACE Rating in 11 drives, the best of all quarterbacks with at least five drives). Kurt Warner from his glory years (1999-2001) with the Rams would have the fourth-best ACE rating, which is closer to where one would expect him to rank. His career ACE Rating is killed by a stretch of games covering three years from 2002-04 when he failed on 21 consecutive potential comeback drives, the longest streak of any player between 1998 and 2009.
Brady has a very high ACE rating -- 1.24 -- but that still doesn't seem to fit his reputation as the best clutch quarterback of the past decade, and he ranks eight places lower in ACE (14th) than he does in QB rating (6th). Brady’s career ACE rating is dragged down by his uncharacteristically poor 2009 season, when he went 1-for-10 on comebacks and had the first below-average seasonal ACE rating of his career (not counting 2004, when he only had one comeback drive). If 2009 is removed, his ACE rating is 1.32, which would be eighth on the list. Brady has also been in easier comeback situations than other quarterbacks. His average degree of difficulty per drive was the easiest of any player in the top 20 of the ACE rankings. Finally, there's the Adam Vinatieri effect: Every time Vinatieri hit a clutch kick in the playoffs, Brady was measured based on what we would expect from an average field-goal kicker instead. This is how Brady can lead all quarterbacks in actual comeback percentage (45 percent) but rank just 14th in ACE.
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