Betting on John Terry Penalty Kicks

Chelsea's John Terry is said to still be haunted by missed penalty kick at the Champions League Finals. Sports bettors too have lost some sleep following the missed opportunity. But was it ever a sure shot?

Penalty Kicks
Eleven meters and the goalkeeper only stand between the kicker and the goal. In the half second that the ball travels the distance, there are other elements too, such as guessing by the goalkeeper, and endless calculations by the kicker.

Another crucial element is statistics.

The simple setting of penalty kicks has drawn considerable academic interest over the years. This is clearly the case for sports bettors. Two players and two possible outcomes. Now let's do the math.

Statistics
Game theory is a major economics field. Do the player and goalkeeper mix their options in the best possible way?

Perhaps there is no difference after all. Analysis of penalty kicks by Pierre-André Chiappori of Columbia University, Steven Levitt of the University of Chicago and Timothy Groseclose of UCLA, came up with the following numbers:

• When kicking to their natural side, kickers scored 77 percent of the time.
• When kicking to the opposite side, a close 70 percent.
• And when kicking to the middle, a slightly higher 81 percent.

For goalkeepers too the numbers are all within the margin of error:

• When guessing center, the stopped 27 percent of the kicks.
• When guessing the kicker's opposite side, 27 percent.
• And when guessing the kicker's natural side, 24 percent.

In other words, statistical research could not reject the hypothesis, namely that the chances of scoring are the same no matter what.

Is this consolation to John Terry and the millions of Chelsea fans around the UK and the world? Perhaps not. Call it a slip.