If Cristiano Ronaldo takes a penalty and aims his shot into the middle of the goal, there is only a 58% chance he will score. If he aims to his left, his chances of scoring go up to 85% and 89% if he goes to his right.
One of the oldest cliches in football is the one about penalties being a lottery.
For many people, however, taking penalties is a science, as evidenced by a growing number of studies and books on the subject by academics and psychologists.
One of the most recent is from a group of Portuguese researchers who have studied thousands of penalties, including those taken by Ronaldo, and built up a database describing the behaviour of individual players while taking a spot kick.
The researchers say they can use the information to predict how a given player is likely to take a penalty, or how a goalkeeper will react, depending on the circumstances of the match, and their recent form.
They hope to sell the information to clubs, with project coordinator Alexandre Real saying it could be worth "between three and 12 points to a team" during a season - enough to make the difference between survival and relegation.
Although many clubs compile their own dossiers on penalties, Real says his group's research has added value in that it identifies individual traits in penalty takers and goalkeepers and how that can vary according to circumstances.
Joao Fialho, a mathematics professor at the American University of the Middle East in Kuwait and also on the research team, said that, for example, when Chile captain Arturo Vidal misses a penalty, he always takes the following one to his left.
On this basis, Fialho said he was able to forecast that when attacking midfielder Vidal took a penalty in the Confederations Cup shootout against Portugal he would shoot to the left - which he did, scoring and sending Portugal goalkeeper Rui Patricio the wrong way.
Vidal had missed his previous penalty, for Bayern Munich against Real Madrid in the Champions League...