It is common knowledge that the effectiveness of implementation is usually measured by the percentage of successful attempts from the total number of them. What is funny.If you play as a defender in hockey, then the chance to score from the blue line is 1%.Attackers by definition are effective, and defenders are not.

Suppose that we are at some point of the field at a distance r from the center of the gate. From this point the gate is also visible under the horizontal angle α and the vertical angle β.

We can form the index of the field point from these three quantities.

There is a nominal index of the point of the field, and still real. Nominal suggests that you are in the uppermost corner. The real depends on the actual values.

Now let’s compare the index points with the real implementation during the whole tournament.
Now we have the opportunity to calculate the average implementation of scoring chances and compare it with the actual.

The player at the realization of scoring chances creates a difference. Goalkeeper, too.If the average goalkeeper was to throw two goals, but in fact he missed one, then he created his team a difference of +1. A player who does not score will receive -1.

Polozov, A.A. The rating system in the game sports and martial arts: Monograph.Ekaterinburg: Publishing house of the USTU-UPI, 1995. 110 p.

Polozov A.A. Encyclopedia rating: economy, sport, society / AMKarminsky, A.A.Polozov, S.P. / M. Economics and Life. 455 s