Per-Snap Impact loaders (S145 · the "SIS")
Proprietary per-snap production metrics built from nflverse snap counts (free, 2012+) by scripts/build-snap-metrics.mjs. The box score is opportunity-blind; normalizing by snaps measures production per opportunity and lets a rotational pass-rusher be compared to an every-down player fairly. SIS is the headline per-snap rate z-scored WITHIN position group (shrinkage-regularized), 0–100.
snap-metrics.json leaderboard (overall + per group) + method/coverage snap-metrics-index.json slug → compact record for the profile panel