Football metrics: Why we should replace yards per play

Nearly every trend arriving in Germany – or Europe in general – comes from the US. No matter what topic, you’ve probably seen it first in the States.

But today, I want to write about a topic where this is not the case. For a few years, there’s been a trend in soccer – a statistic called “expected goals”. Every area on the field has a probability to score a goal (it gets higher when the distance to the goal gets smaller) and when you shoot from a position and multiply it with the number of shots, you get a number that represents the “expected goals (xG).”

Now, there’s a comparing statistic in American football: “expected points” or “expected points added” – it exists for a long time, ESPN explained it 2012 already, but it still isn’t a popular stat until today.

Expected Points and EPA explained

To calculate the expected points, every down & distance gets a number based on analysis of former plays from this down & distance. If you have the ball on your own 20-yard line with a 1st&10, you’ll score +0.4 net points more than your opponent who does not have the ball at the moment at your next play. If you have the ball with a 1st&10 at the opponents 20-yard line, you’ll score +4 net points more than your oponnent.

Now, let’s get to an actual play: You have the ball at midfield with a 1st & 10 and you get a 5-yard gain. The first situation had +2 EP, the second one (2nd & 5 at the 45) +2.1. With this 5 yards, you gained +0.1 expected points added.

Advantages and disadvantages of EP / EPA

This metric shows how good a team is getting the ball to the other side and preventing bad situations on offense and defense. It does not show how efficient a team is scoring points and it does also not work for garbage time, when a team with a big lead rather runs time off the clock than scoring.

But it shows which team is superior and which team plays better.

Yards per play is a value to demonstrate efficiency. But it does not accomodate the value of getting a new first down after a 4th & 2 in the redzone. The value of a certain play gets lost and a team that is strong in the redzone gets a lower value than a team that throws 60-yard bombs all the time and never scores a touchdown because it cannot convert 3rd- and 4th downs in the redzone.

So, to show which team “should have won”, expected points are a better basis for debate than yards per play. If you want to look them up, shows the expected points for offense, defense and special teams after every game.

Max Sachs is an international Packers fan from Germany. As a part of the Packers Germany, he tries to convince everyone around him to cheer for the greatest franchise on earth - or to start with, for American football in general. You can find him on Twitter @KaesekopfDE (the german translation for cheesehead).