True Pass Efficiency

The standard measure of pass efficiency is made by dividing total passing yards by pass attempts. The NFL defines passing yards as yards gained (or lost) during all pass completions minus yards lossed in sacks. Pass attempts are defined as actual throws but do not include pass plays that result in sacks.

To date, my research shows conclusively that pass efficiency (yards per attempt) is the best measure of a team's ability to pass compared to any other. Other measures, such as total passing yards or completion percentage, simply do not correlate with winning as well as efficiency. The same is true on the defensive side of the ball.

But an even better efficiency stat, one that includes sacks as "pass attempts," should correlate with winning even better than the standard efficiency stat I've been using so far. Sacks measure a teams pass-blocking ability, quarterback mobility and vision, and the ability of receivers to get open--all part of a team's total passing proficiency.

By using data from the 2002-2006 NFL regular seasons, the correlations of the passing efficiency stats with winning are shown below. Both the standard efficiency and the improved efficiency (counting sacks as pass attempts) are listed for both offense and defense.


The result is better win correlations for both offensive and defensive "improved" pass efficiency calculations. This indicates that the game-by-game win-probability model I have been using would likely be improved by using the new pass efficiency stats.