Fenwick%
also: FF% · unblocked shot attempt percentage
Corsi with blocked shots removed — a slightly cleaner read on possession, and a better predictor of goals.
FF% = unblocked attempts for / (unblocked attempts for + unblocked attempts against)Fenwick counts goals, shots on goal and missed shots, and throws out blocked shots. The argument is that shot blocking is a repeatable team skill rather than noise, so crediting the shooting team for an attempt that never reached the net overstates what happened.
In practice Corsi and Fenwick correlate above 0.95 and rarely disagree about who controlled a game. Fenwick is marginally more predictive of future goals; Corsi has the larger sample and therefore stabilises faster over a short stretch.
The practical reason to prefer Fenwick when computing your own numbers from play-by-play: blocked shots are the one event type where feeds disagree about which team to credit, so excluding them sidesteps an attribution question entirely.
Treating the Corsi/Fenwick gap as meaningful. For most teams it is under a point and reflects how much their opponents block, not a difference in how they play.
Where to get it
Related
Fenwick% from the API
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