The best quarterback is not always part of the most stable quarterback room.
QB Stability is PFM’s grade for the entire quarterback situation. Half of the score comes from quarterback play. The other half comes from availability, job security, age and the depth behind the starter. The goal is not only to identify the most talented passer. It is to show which teams can trust the position through the pressure, injuries and uncertainty of an NFL season.
A standard quarterback ranking starts with one player. How accurate is he? How much can he create after the first read disappears? Can he carry an offense when protection breaks down?
Those questions matter, and they drive half of the QB Stability grade. They still leave out too much. A team can have an elite starter and a fragile quarterback situation. Another team can have a less exciting passer but far fewer ways for the position to fall apart.
How PFM Calculates QB Stability
50%QB Play
20%Availability
15%Job Security
10%Age
5%QB Depth
Let’s take an in-depth look at QB Play. We will dive into the other sub formulas in another post.
QB Play — 50%
PFM separates a quarterback’s current statistical performance from the overall stability of his team’s quarterback room.
The QB Play metric measures how the quarterback performed on the field. It uses nflverse and nflfastR regular-season play-by-play data through the selected week. Playoff statistics are not included.
Only legitimate quarterback dropbacks are counted. Special-teams plays, kneel-downs and spikes are removed. A play qualifies as a dropback when it is identified as a quarterback dropback, pass attempt or sack.
A quarterback must have at least 150 dropbacks to receive a QB Play rating.
The QB Play Formula
QB Play =
35% EPA per Dropback
20% Success Rate
20% Touchdown Rate
15% Interception Avoidance
10% Sack AvoidanceEPA per Dropback: 35%
EPA stands for Expected Points Added. It estimates how much each dropback improved or hurt the offense’s expected scoring position.
Positive EPA is good. Negative EPA is bad. Because sacks are included as dropbacks, quarterbacks are held responsible for the effect those plays have on the offense.
This receives the most weight because it captures overall efficiency better than passing yards or completion percentage alone.
Success Rate: 20%
Success Rate measures how often the quarterback’s dropbacks are classified as successful by the nflverse play-by-play model.
EPA can be influenced by a few enormous plays. Success Rate helps us determine whether the quarterback consistently keeps the offense moving.
Touchdown Rate: 20%
PFM calculates touchdown rate as:
Passing touchdowns + 55% of rushing touchdowns
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Total quarterback dropbacksRushing touchdowns receive partial credit. This recognizes the value of a quarterback’s rushing ability while keeping QB Play centered primarily on passing and dropback performance.
Interception Avoidance: 15%
Interception rate is calculated as:
Interceptions
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Pass attemptsLower is better. The quarterback with the lowest interception rate receives one of the highest Interception Avoidance ratings.
Sack Avoidance: 10%
Sack rate is calculated as:
Sacks
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Quarterback dropbacksLower is better. This does not assume every sack is entirely the quarterback’s fault, but avoiding unnecessary pressure and getting the ball out remain important parts of quarterback play.
Converting Statistics Into PFM Ratings
PFM does not multiply raw statistics directly into a 0–100 score.
Each of the five statistics is ranked against the other qualifying quarterbacks. That percentile is then converted to the PFM football-rating scale:
PFM rating = 60 + (percentile ÷ 100 × 35)That produces a fan-readable scale:
90–95: Elite
85–89: Very strong
80–84: Good
75–79: Average to above average
70–74: Below average
60–69: PoorFor EPA, Success Rate and Touchdown Rate, higher is better. Interception Rate and Sack Rate are reversed so that lower rates receive higher scores.
The five converted ratings are then combined using the QB Play weights.
QB Stability Is Not the Same as traditional QB Rating
Most QB Ratings focus on the starter’s performance. QB Stability steps back and grades the complete setup. Reading the two together gives a much clearer answer than either number can provide alone.
| Question | QB Rating | QB Stability |
|---|---|---|
| Who is being judged? | The starting quarterback | The entire quarterback room |
| What matters most? | Current quarterback performance | Play, availability, job security, age and depth |
| What does a high grade mean? | The starter gives the offense high-level play | The team can trust the position across more situations |
| Can an elite quarterback rank lower? | His talent still grades highly | Yes, when the full room carries more risk |
Five Examples That Show Why the Difference Matters
The cleanest way to understand QB Stability is to look at situations where the starter’s reputation and the full-room grade do not say the same thing.
Elite Talent, Reliable Backup
Joe Burrow Is the Star, Flacco is the Security Blanket
Burrow’s place among the NFL’s best quarterbacks is not the debate. His timing, ball placement and control of Cincinnati’s passing game give the Bengals a real advantage. QB Stability asks what happens if he gets injured again?
Even at his age, Joe Flacco is still one of the best backups in the NFL. Sure he lacks explosive abilities but Flacco still can make every throw on the field. Add journey Josh Johnson to the mix as a 3rd string QB and you have one of the best quarterback rooms in the league. See Cincinnati’s full team outlook.
The Starter Is Great. The Summer Is Uncertain.
Patrick Mahomes Shows Why Availability Cannot Be Ignored
Mahomes can solve late downs in ways almost no quarterback can match. Kansas City’s current question is not whether he is talented enough. It is how much normal movement and off-script creation he has while working back from the ACL injury that has shaped Kansas City’s summer.
That is exactly where QB Stability differs from a quarterback talent list. Mahomes can remain one of the league’s best players while availability creates a separate question for the full room. Bringing in Justin Fields this offseason was not talked about enough. KC is the perfect scenario for Fields. If he has to start, the pressure will be off him for the first time in his career. See Kansas City’s full team outlook.
Age Changes the Floor
Aaron Rodgers Can Still Make Throws But His Limitations Can’t be Ignored
Rodgers’ experience and arm talent can take Pittsburgh to the playoffs as we saw last season but his age and mobility are concerns. The Steelers are also changing offensive systems around an older quarterback and the backup situation isn’t clear yet.
QB Stability does not say age makes Rodgers ineffective. It says Pittsburgh’s floor is tied closely to him staying healthy and decisive. That is a different claim, and it is the one a season-long stability grade needs to make. See Pittsburgh’s full team outlook.
Job Clarity Matters
Cleveland’s Quarterback Competition Changes the Grade Before Week 1
Cleveland can like traits in more than one quarterback and still have an unstable room. An unsettled starting job affects practice reps, the offensive game plan and how quickly the team can build around one player. Is Deshaun Watson the starter or will Shedeur Sanders continue to build on last seasons promise.
The grade is not predicting who wins the competition. It is recognizing that a team with no clear starter carries more uncertainty than a team that already knows who will run the offense. See Cleveland’s full team outlook.
More Stability Than Star Power
Sam Darnold and Seattle Show the Other Side of the Formula
Darnold does not need to rank with Mahomes, Allen or Burrow for Seattle’s quarterback room to be stable. A confirmed starter, a defined play-action role and an offense designed to keep him out of constant rescue football can give the Seahawks a dependable base.
That does not mean Darnold is the better individual quarterback. It means a room can have fewer immediate questions than the starter’s national reputation suggests. Stability and star power are not interchangeable. See Seattle’s full team outlook.
What the Rankings Are Really Telling You
A high QB Stability grade means the team has fewer reasons to panic at the most important position. The starter can play, the job is clear and the room has enough support to keep one bad stretch from turning into a season-long crisis.
A lower grade can point to several different problems. One team may have an open competition. Another may have a great starter with real availability concerns. A third may trust the starter but have almost no answer behind him. The number matters, but the reason behind it matters more.