Expected Points/Net Expected Points (NEP)
Every single situation on the football field has an expected point value; that is, how many points an average team would be expected to score in that situation (given down, distance-to-go, and yard line). For example, the Chiefs may be facing the Pittsburgh Steelers, with a third-and-two on the 50-yard line. That's a ton of variables, but luckily, numberFire has data from the past dozen years of every single play, so most situations have come up at least once. According to our data, an average team may be "expected" to score 1.23 (estimated number) points on that drive. However, Jamaal Charles reels off a 32-yard run to bring the Chiefs into the red zone, increasing the "expected" point value of the next play to 4.23 (still an estimated number) points. Jamaal Charles then gets credit for the difference, in this case 2.96 points, as his NEP total. That's Net Expected Points.
Since passing is often more efficient than running the ball, you'll usually see running backs with negative NEP per play scores, meaning that they are losing their team expected points every time they touch the ball. Receivers and tight ends, meanwhile, will usually have high, positive NEP per play scores, since receivers don't touch the ball unless it's a high-yardage completion. Quarterbacks can be in the middle, either positive or negative: completions typically help their score, while incompletions lower it. So when you're looking at NEP, it's important to look at the numbers based on position. Expected points do not take score and timeleft into account like win probability, and as a result, are a better measure of pure efficiency (since teams will alter their game plan significantly based on score and time).
