NHL Coverage
Expected goals, possession metrics, and why plus-minus is lying to you.
The Analytics Revolution in Hockey
Hockey analytics has come a long way from the early days of Corsi and Fenwick. Modern expected goals models incorporate shot location, shot type, traffic, rebound status, and pre-shot movement to estimate the probability of any shot becoming a goal.
Key Metrics
Team-Level
- xGF% — Expected Goals For percentage. Measures quality-adjusted shot generation vs. prevention.
- CF% — Corsi For percentage. Raw shot attempt differential (a possession proxy).
- PDO — Shooting % + Save %. Teams far from 100 are likely to regress.
Player-Level
- GAR — Goals Above Replacement. Total value metric.
- xG Impact — How much a player improves/hurts expected goals when on ice.
- WAR — Wins Above Replacement, adapted for hockey.
Why Traditional Plus-Minus Is Broken
Traditional plus-minus in hockey is one of the worst widely-cited stats in all of sports. It's polluted by:
- Teammates — Playing with great players inflates your plus-minus
- Zone starts — Players deployed in the offensive zone look better
- Goaltending — Your goalie's save percentage directly affects your numbers
- Score effects — Trailing teams generate more shots, distorting metrics
Modern adjusted plus-minus models (RAPM) attempt to isolate individual impact, but even these require large samples to stabilize.
The Skeptic's Take: If someone cites raw plus-minus to evaluate a hockey player, politely direct them to this page.