Also called the pass efficiency rating, a statistical measure of the overall ability of a quarterback. As with most statistics, it lies... awarding a higher rating to quarterbacks who throw short passes

^{*} (see:

West Coast Offense), completely ignoring a quarterback's

escapability and running ability, and punishing quarterbacks in offensive schemes where rushing is prevalent

^{‡}.

The following equation, adopted in 1973, is used to calculate quarterback rating in the NFL (college football uses a different scheme):

(CP + YG + TP + IP) * 16.67
Where:
CP = (completion percentage - 30) * .05
if CP < 0, CP = 0
if CP > 2.375, CP = 2.375
YG = (average yards gained per attempt - 3) * .25
if YG < 0, YG = 0
if YG > 2.375, YG = 2.375
TP = touchdown percentage * .2
if TP > 2.375, TP = 2.375
IP = 2.375 - (interception percentage * .25)
if IP < 0, IP = 0

Using that equation, you can see that the highest possible quarterback rating is 158.3.

Steve Young holds the record for the highest actual QB rating in a season, with 112.8 in 1994 (461 attempts, 324 completions, 3,969 yards, 35 touchdowns, 10 interceptions).

* While YG compensates for short passes, short passing schemes result in a much higher completion percentage, and yards after catch (YAC) are all credited to the quarterback as well. So, if a QB throws a pass to a receiver one yard downfield, who then jolts down the field for forty more yards, the quarterback is rewarded with a 41 yard pass.
‡ While a team that focuses on the running game will tend to have a quarterback with fewer attempts, they are also more likely to run on every down inside the red zone, forcing a quarterback to earn his touchdowns on long, low percentage passes.