If you're a die-hard fan, it's important to understand hockey statistics. The Corsi, FenClose, and PDO may seem like obscure terms, but they are vital statistics that shed light on how a team (and even a single player) is performing at a given time. Read on to learn about these important hockey statistics.

The Corsi

If you know the concept behind plus/minus, you already understand the Corsi. The term is just like plus/minus, only instead of counting goals for and against, the Corsi counts total shot attempts for and against, goals, saves, shots that miss the net, and shots that are blocked. It is named for the person who brought the term to prominence, Buffalo Sabres goalie coach Jim Corsi. He was looking for a way to measure the workload his goalies had to face during a game. His reasoning was that a shot attempt, whether it reached its intended target or not, required a reaction from the goalie.

The statistic is also a pretty good measure of puck possession and how much time a team or player is spending on each end of the ice. A player or team with a high Corsi is spending more time in the offensive zone on the attack, while a player or team with a negative Corsi is trying to defend and constantly chasing the puck.

Why It Matters

The Corsi has predictive value and is more repeatable than plus/minus, which is heavily impacted by goaltending and luck. Teams and players have an impact on the number of shots they generate, but they don't always control how many of those shots or which ones go into (or stay out of) the net.

The Corsi is not perfect. When it comes to individual players, their roles must be considered. A player who is put into defensive roles — starting most of his shifts in the defensive zone and against better competition, for example — is probably going to see his Corsi numbers take a hit, especially when compared to a player who plays softer minutes (more offensive zone starts, going up against weaker competition).

The Fenclose

The FenClose refers to the percentage of unblocked shot attempts a team takes in a game when the score is close, within one goal or tied. For example, if the Toronto Maple Leafs and Montreal Canadiens combine to take 100 unblocked shot attempts with the score close, and Toronto had 38 of those attempts, Toronto would have a FenClose percentage of 38 percent.

When teams take the lead or fall behind by two or more goals, they tend to change the way they play, especially late in the game. A team that has a two- or three-goal lead in the third period will generally play a more passive, careful game than a team that is trailing by the same margin. When the game is close or even tied, teams are playing more within their system — making the FenClose a better reflection of their true talent level.

The PDO

The PDO reflects save and shooting percentage. It's a quick way to look for teams and players that are riding a hot streak and playing over their talent levels during a given period.

The PDO also helps evaluate a single player's current production. For example, if a player who has been an 8- or 9-percent shooter for his career suddenly has a season where he shoots at 18 or 20 percent, he's likely to see his numbers come crashing down the next season.

PDO Example

Take the case of the Anaheim Duck's Ryan Getzlaf, who was a 12-percent shooter for most his career. Getzlaf finished the 2013-14 season by scoring on just five percent of his shots. The Ducks, as a team, scored on just seven percent of their total shots with him on the ice, leading to one of the worst seasons of Getzlaf's career. His PDO was a career-low 99.7 that year. But the PDO shows that the season was an outlier for Getzlaf. His PDO jumped to 101.4 in the 2014-2015 season and a whopping 106.1 in 2015-2016, the highest of his career.

As you can see, the Corsi, FencClose, and PDO may seem like obscure terms, but they help show how teams and players are performing.

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