• Hockey fans have lived through a translation problem for about fifteen years now.
  • Advanced stats entered the sport through hockey analytics communities in the early 2010s, borrowed concepts from basketball and hockey analytics work, and eventually made their way into mainstream broadcasts and team decisions. Most fans still don't know what they mean. That's okay. Here's the plain version.
  • Corsi is the simplest entry point. Take all shot attempts — on net, blocked, missed — when a player is on the ice. Compare them to what the other team generated. That's your Corsi. Think of it as possession volume. A player with a 55% Corsi is driving play in the right direction more often than not. Teams use it to evaluate who drives puck possession and who gets buried in their own end.
  • Expected Goals (xG) is more sophisticated. Not all shots are equal. A wrister from the point is not the same as a one-timer from the slot. xG assigns a probability to each shot based on historical data — location, type, whether it came off a rush or from a cycle. A player with a high xG is getting to high-danger areas consistently, regardless of whether the puck goes in.
  • Fenwick is Corsi minus blocked shots. Some analysts prefer it because blocked shots involve a defender actively making a play, which muddies the possession signal. Same idea, slightly cleaner data.
  • PDO is the sum of a team's shooting percentage and save percentage when a player is on the ice. It's used as a luck indicator. If your PDO is above 1.000, you're probably getting bounces. If it's well below, you're due. Over a full season, PDO almost always regresses toward 1.000 — which means the players with extremely high or low PDOs in a half-season are more likely to be beneficiaries or victims of variance than genuinely elite or terrible.
  • What these stats do well: they capture elements of play that the eye test misses — quiet contributors, players who are always in the right position, shot suppression that doesn't show up on the scoresheet.
  • What they miss: context, competition, clutch performance, and the reality that hockey is a low-scoring sport where random variation dominates over small samples. A 20-game stretch of Corsi data tells you very little. 200 games tells you more.
  • The practical value for average fans is simple — don't trust any single stat. Look at the trends, the context, and the player role. The numbers are a lens, not a verdict.