Success rate (football)

Success rate measures the share of American football plays that achieve a positive outcome relative to the down and distance faced, rather than judging every play by total yards gained. A short gain on third-and-two can be a "successful" play even though a long gain on third-and-fifteen that still fails to convert is not.

A common threshold set defines success as gaining at least 40 to 50% of yards needed on first down, 60 to 70% on second down, and the full distance, a conversion, on third or fourth down, though exact thresholds vary by analyst and provider. This makes success rate a binary, per-play measure, in contrast to expected points added, which assigns a continuous point value to every play regardless of whether it crossed a threshold.

Because it is not skewed by a single explosive play the way yards-per-play or EPA totals can be, success rate is considered a relatively stable, sample-efficient way to evaluate offenses and defenses, especially over a handful of games. It is often used alongside EPA, since one captures consistency and the other captures magnitude of value. The pitfall is that, because threshold definitions differ across sources, success-rate figures are not always directly comparable between two analysts' models without checking their exact definitions first.