Corsi, Fenwick, PDO. Even-strength vs all situations vs 4-on-5. WOWYs. What does it all mean? And now, to confuse the matter more, the NHL has renamed Corsi and Fenwick to Shot Attempts and Unblocked Shot Attempts (heretofore referred to as SATs and USATs on this blog).
First, we need to specify that most stats are given at even-strength play. The majority of the game is played at 5-on-5, so it makes sense that those numbers are the most utilized ones. That’s not saying the other ones aren’t important. They have their uses (such as trying to discover why a team’s powerplay is horrendous). But when you’re analyzing a team or individual’s performance, you want to look at the bulk of their work and not special circumstances. In fact, the NHL’s new stats site only looks at 5-on-5 play. If you want further insights, you need to visit War on Ice or HockeyAnalysis. (That’s not the only thing wrong with the new stats site but alas, they tried and it’s a start. You can read a really good review on the new site here by Thomas Drance.)
Now, let’s talk about SPSV% (Shooting%+Save%) – previously known as PDO. A team’s SPSV% is simply their shooting percentage plus their save percentage (S%: goals scored divided by shots taken; SV%: saves divided by shots faced.) It works under the impression that individuals eventually regress to their own 100%, and so does a team. So if you have a low SPSV%, it will eventually climb – their low shooting or save percentage (or both!) will go back to normal. A high SPSV% will eventually drop. Regression to the mean! For those not statistically inclined, that’s the phenomenon that if a variable is extreme on its first measurement, it will tend to be closer to the average on its second measurement—and, paradoxically, if it is extreme on its second measurement, it will tend to have been closer to the average on its first.
Moving on to Corsi and Fenwick (shot attempts [SAT] and unblocked shot attempts [USAT], respectively). Corsi/SAT is every single shot taken. To be specific: “shots on goal + missed shots + blocked shots.” Fenwick/USAT is only “shots on goal + missed shots”. Some prefer one to the other. Why are they important? Because if you’re taking a shot, you have the puck. The more you have the puck, the likelier it is of scoring goals.
Those are the three most used terms, I believe. WOWYs are pretty important and others have explained it far better than I ever could. From Hockey Analysis:
WOWY (with you or without you) is an analysis that looks at how a player performs when playing with or not with his teammates. A WOWY analysis can tell you which players play well together, which players make their line mates better players, and which players are most valuable to a team. For teams this can help you set the most optimal lines as well as identify players that are vital to the success of the team and which are secondary contributors.
If you’re interested in learning more about stats, there are lots of resources available (just google hockey advanced stats or click on any of the links in this post). And if you’re not interested, hopefully this will at least help you understand the new terms being bandied about by everyone in correlation with the old terms of Corsi, Fenwick, and PDO.