Adjusted QBR (Total Quarterback Rating) is an ESPN metric that evaluates a QB's overall performance on a 0-100 scale, adjusting for the strength of opposing defenses faced, game situations (score, time, field position), and separating QB contribution from teammates. It's a comprehensive stat that credits QBs for success in tough spots (e.g., clutch plays, avoiding sacks) and penalizes them for mistakes, aiming to show how much a QB contributes to winning beyond simple stats like completion percentage.
Key components and adjustments:
- Contextualizes plays: A 5-yard gain on 3rd-and-4 is more valuable than on 3rd-and-14; a TD in the 2nd quarter (tied) is better than late in a blowout.
- Accounts for difficulty: Adjusts credit based on game leverage (score, time, field position) and opponent strength, giving more credit for success against strong defenses.
- Includes all contributions: Considers passing, rushing, turnovers, penalties, and even designed runs and scrambles.
- Divides credit: Allocates credit between the QB and teammates (e.g., receiver, blockers) for each play.
- Removes "garbage time": Low-leverage plays late in decided games are discounted.
How it works (in simple terms):
- Calculate Expected Points Added (EPA) for each play based on game situation.
- Adjust EPA for QB contribution, difficulty, and opponent.
- Discount "trash time" plays.
- Average these adjusted plays to get a value on a 0-100 scale, where 50 is average.
In essence, Adjusted QBR gives a holistic view, showing how much a quarterback truly impacts winning by accounting for the specific challenges and contexts of each play, unlike traditional passer ratings that rely solely on aggregate stats.