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Adjusted Comeback Efficiency

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.

 

QB Rankings and Article source after the jump

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 X

 

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).

 

Source

Much more details at the originating article ...