Alt passing yards (short for alternative passing yards) is an analytical metric used primarily in football analysis to provide a different perspective on a quarterback's true passing performance compared to the official NFL passing yards statistic.
The core principle behind alt passing yards is to credit the quarterback only for the yards gained from passes that were accurately thrown and catchable. It aims to filter out:
- Yards gained solely due to the receiver's actions after the catch on poorly thrown passes (e.g., low, high, behind the receiver) that the receiver managed to catch anyway.
- Yards gained due to defensive errors, like dropped interceptions or blown coverages, on passes that weren't well-placed.
Calculation typically involves:
- Assessing pass location: Using advanced tracking data to determine if a pass was "on-target" or placed optimally for the receiver.
- Applying a yardage adjustment: Assigning yardage credit based on where the accurate pass should have been caught, rather than where the receiver actually caught it (if they had to adjust significantly). Often, the yard line where the catch occurred is used for accurately thrown passes.
Key Applications:
- Evaluating QB Accuracy & Decision Making: Provides a clearer picture of a QB's fundamental passing skill by isolating factors outside their direct control (receiver YAC on bad throws, defensive luck).
- Predictive Analysis: Often considered more stable and predictive of future QB performance than raw passing yards, which can be heavily influenced by scheme, receiver skill, and luck on a game-by-game basis.
- Performance Context: Helps explain why a QB might have high/low raw passing yards on a given day despite good/bad actual throws.
Example: If a QB throws a pass 5 yards behind the receiver at the line of scrimmage, but the receiver adjusts, catches it, and runs 40 yards for a touchdown, the QB gets credited with 45 official passing yards. Alt passing yards might credit the QB with significantly less (e.g., only the ~5 air yards to the intended, on-target spot), as the bulk of the yards were due to the receiver's exceptional effort after an inaccurate throw.
Notable Providers: Various analytics companies and platforms calculate alt passing yards (sometimes under similar names like "Passing Yards Over Expected", or using EPA-based methods), often utilizing player tracking data for accuracy.
In essence, alt passing yards measures the passing yardage a quarterback truly earned through accurate throws, providing a valuable counterpoint to the traditional statistic.
