Your team was down a touchdown in the final moments of the game but just scored a touchdown, should they simply tie the game with an extra-point or go for the win and attempt a two-point conversion?
For the most part, NFL coaches go for the extra-point and the tie and take their chances in overtime. But is this the optimal decision? We decided to crunch the numbers.
History of the Two-point Conversion
In the NFL, the two-point conversion was first instituted in 1994 with the first successful conversion occurring in the first week of the season when Tom Tupa ran a faked extra point for the Cleveland Browns (vs. Cincinnati Bengals). Two-point conversions have been used in collegiate football since 1958, the Canadian Football League since 1975 and was part of the American Football League throughout its existence (1960-69).
But since their inclusion into the NFL, how often are two-point conversions successful?
The two-point conversion gives teams the ability to turn a touchdown play from a typical seven point play into an eight point play by again taking the ball into the end zone through either a passing or rushing play after the original touchdown was scored and instead of an extra-point kick.
But how often do two-point conversions work out?
Between 1994 and 2012, a total of 1,469 two-point conversions have been attempted in the NFL with a total of 658 being successfully converted, which means that on average a two-point attempt is successfully converted 44.79%.
For trivia buffs, the record for most two-point attempts in a single season is held by the 2002 New Orleans Saints with 11, in which they converted on just 4 for an average of 36.4%. The record for most successful two-point conversion attempts is held by the 1994 Miami Dolphins and 1997 Minnesota Vikings with 6 each - Dolphins on 10 attempts and the Vikings on 8 attempts.
How do these two-point conversion success rates compare to extra-points?
For those who don’t know, an extra-point is a kick that occurs after a touchdown is scored, which is attempted from 20 yard line and upon a successful conversion gives a team an additional point on the play.
Extra-points are converted so often that New England Patriot coach Bill Belichick has said "Philosophically, plays that are non-plays shouldn’t be in the game. I don't think it is good for the game. Extra points, when the odds are in the 99 percent range in extra points it is not a play.”
And whether you agree with his philosophy, he is mostly in terms of his estimate of extra-points odds.
More specifically, between 1990 and 2011, there were a total of 23,684 extra-points kicked with just 359 being missed by way of either a block or by a complete miss. This equates to a success rate of 98.48%.
For more on extra-points and how often they are made, check out: How Many Extra Point Kicks are Missed on Average in the NFL?
So Two-point Conversion or the Extra-point?
One way we can compare the two plays and which is the better choice is to look at the estimated point value of each prior to the actual success or failure of each. We can do this by simply multiplying the point value of the play when successful by the probability of success.
For two-point conversions, the estimated point value is calculated by multiplying the two points by the 44.79% historical conversion percentage:
Two-point conversions = 2 points x 44.79% = 0.896 points
Essentially, by this calculation, before the two-point conversion is attempted it’s worth approximately 0.896 points. How does this compare to extra points?
For extra-points, the estimated point value is calculated by multiplying the one point you gain for a successful kick by the 98.48% historical success rate:
Extra-points = 1 point x 98.48% = 0.985 points
Essentially, by this calculation, before the extra-point attempt is attempted it’s worth approximately 0.985, which is 0.09 points higher than that of the two-point conversion attempt making it the more optimal decision.
So if your team has just scored a touchdown to get within one point of tying the game, they should go for the tie instead of the win with the extra-point which is not only a near guarantee but is the more optimal choice from an estimated point value perspective.