Impact Grade Methodology

01 · The model

How a Grade Is Built

Every board works the same way. A position's main stats are adjusted so different eras line up, blended by weight into one standardized score, and that score is placed on the scale.

75 is an average qualifying season.
z is how far above or below average a season was: 0 is dead average, +1 a clearly above-average year.
Slope turns that gap into points, about 8 per step above average for players and 8.11 for teams, so a 90 means the same for a cornerback or a whole offense.
Held to a 50–100 range and rounded to one decimal place.

Where seasons land

Each board is standardized to a mean of 75, so a 90 sits in the top few percent at any position. A 90 corner and a 90 offense are equally rare.

Each season is centered on its own year before scoring, so a 92 means the same thing in 2001 and 2025. Small samples are pulled toward the baseline, so a few hot games cannot produce an all-time grade.

02 · Offense

Skill & Line

Efficiency counts more than raw volume, and production is measured against what a readily available backup would have done, so piling up numbers in a heavy workload only helps if you beat that bar.

Quarterback	Passing efficiency from EPA per dropback, success rate, ANY/A and completion over expected, plus designed-run value.
Running Back	Rushing and receiving value over replacement, yards from scrimmage, touchdowns and rush yards over expected.
Wide Receiver	Receiving value over replacement and target share, with Next Gen separation and yards after the catch over expected.
Tight End	The same receiving model graded against tight ends, plus a blocking component from 2019 on.
Offensive Line	Pressure and sacks allowed and run-block quality, ranked within tackle, guard and center (2019 on).

03 · Defense

Front & Back Seven

Box-score disruption, plus coverage measured by the rates a player allows.

Interior DL	Pass- and run-disruption value, sacks, QB hits and tackles for loss, totaled over the season.
Edge Rusher	Mostly pass-rush disruption and sacks, with run defense added.
Off-ball LB	Run defense, coverage and pass rush, weighted together.
Cornerback	Coverage stinginess from passer rating and yards allowed per target, plus how often he is thrown at.
Safety	Coverage efficiency, takeaways and tackling, with diminishing returns so a single big year cannot dominate.

04 · Special teams

Kicking & Punting

Everything is measured against expectation. Field goals are judged against distance, punts against field position.

Kicker	Field goals made over a distance-adjusted expectation, plus EPA, long-range makes and clutch kicks.
Punter	Net and gross yards over expectation and pinning inside the 20, adjusted for where the punt started.

05 · Teams & units

Team & Unit Grades

Unit grades blend drive- and play-level outcomes, adjusted for strength of schedule.

Offense	Points per drive, EPA and success rate, red-zone finishing, explosive plays and ball security.
Defense	The offensive blend mirrored on what the defense allowed and forced, so takeaways and sacks count as positives.
Special Teams	Net special-teams value across kicking, punting, returns and coverage.
Team (overall)	The point margin those three units predict, with offense and defense weighted equally and special teams a small share.

The team grade is a predicted point margin, not an average of the three units. Because the units are mostly independent, a complete team can grade higher than its own best unit. The all-time leader is the 2007 Patriots, at 98.