Hockey Analytics For Beginners

What is “WAR”? What is the difference between xG and just G? Do you want a high SV% and a low GAA, or vice versa? For all these questions – and some others – our glossary of basic analytics terms, acronyms, and statistics will help you learn to talk puck like a pro.

First, though, a quick disclaimer. While stats are an incredibly useful tool for evaluating both teams and players, they’re not the be-all and end-all of value and should be treated the same way as any other tool – used judiciously, in conjunction with a healthy amount of common sense. With that all said, though, let’s get into the glossary.

The Basics

Let’s start off with some of the most basic terminology – if you’re already a hockey pro, you can probably skip this one, but for the newbies, here’s a quick rundown.

Goals

A goal is, simply put, when a puck goes in the net. There are obviously some rules on what counts in that sense and what doesn’t, but that’s a topic for another time. For our purposes, the simple definition is the best. A goal is worth one point.

Assists

An assist – sometimes abbreviated as ‘A’ or referred to as an apple – is a helping hand when it comes to scoring a goal. Like a goal, assists have some rules. For a player to earn an assist, they have to have control of the puck – which is to say, they have to be moving it in an intentional way – right before the goal-scorer. There can be up to two assists per goal, depending on how many people on the goal-scorers team had control of the puck just before they did. An assist is also worth one point.

Points

This can have two meanings. When it comes to an individual, it is a tally of how many goals and assists a player has earned. This is one way of measuring a player’s offensive capabilities. When it comes to a team, it is a tally of how many games they have won. This is one way of ranking teams.

Wins

This is a pretty easy one. If a team ends the third (and final) 20-minute period of the game with more goals than their opponent, they win. A win is worth two points.

Losses

It’s also pretty easy. If a team ends the third (and final) 20-minute period of the game with fewer goals than their opponent, they lose. A loss is worth zero points.

Overtime

If a team ends the third period of a game in a tie, the game goes to overtime. This has its own specific rules for point value. If a team wins in overtime, they earn two points. If a team loses in overtime, they still earn one point.

Penalties

Penalties are when a player is punished for breaking the rules. They are removed from the ice and have to sit in the penalty box for a certain amount of time, and their team must play with one less player. If a goalie takes a penalty, a skater serves in their place. The two most common types of penalties are minor penalties, which are two minutes long, and major penalties, which are five minutes long. In rare cases, a misconduct penalty worth 10 minutes will be awarded. Unlike minor or major penalties, the team can replace the penalized player on the ice. These are occasionally coupled with game misconducts or match penalties, which eject a player from the game entirely.

Drawn Penalties

When talking about penalties, people often use the term “drawn penalties” or refer to the amount of penalties a player “draws.” This refers to the number of times an opposing player has a penalty called for something they do to that player. There’s a variety of reasons someone might draw a lot of penalties, but it’s usually a good thing for their team, as it gives them more advantages in play.

The Acronyms

Stats guys – myself included – like to use a lot of acronyms. This can be useful when you’re talking about the same stats all the time and don’t want to have to type or write out the longer phrase each time. However, it can be confusing for those who don’t know what these collections of letters stand for. I’ll break down some of the most common ones here.

A1

This refers to a primary assist. A primary assist is awarded to the player – if there is one – on the goal-scorers team who had control of the puck just before the goal-scorer.

A2

This refers to a secondary assist. A secondary assist is awarded to the player – if there is one – on the goal-scorers team who had control of the puck just before the player awarded the primary assist.

PIM

This stands for Penalty Infraction Minutes but is often referred to as just penalty minutes. It represents the total length of time of all penalties a player has taken. So, if someone takes two two minute penalties and one five-minute penalty, they have a total of nine PIM.

SOG

This stands for Shots On Goal. It seems fairly straightforward, but the definition is pretty specific. For something to count as a shot on goal, it must direct the puck towards the net (so not high or wide) and either go into the goal or be stopped by the goalie (so shots that hit the crossbar or get blocked on their way to the goal don’t count). This definition is especially important because shots on goal are often used as a way to calculate both how many saves a goalie makes and how good a team’s defense is.

TOI

This stands for Time On Ice. It represents the amount of time a player spends on the ice – that is, actually playing – in a single game. A higher TOI usually means that a player is trusted more by a coach, as it’s an indication that the coach thinks the player brings value to the team when they’re playing – otherwise, a coach might play them less.

EV

This stands for Even Strength, also referred to as full Strength or five on five. It’s the standard for a hockey game when no penalties are involved, with five skaters and one goalie from each team on the ice.

PP

This stands for Power Play. A team receives a power play when one of their players draws a penalty, meaning that an opposing player is sent to the penalty box. They then have one more skater on the ice than their opponent, giving them an advantage.

PK

This stands for Penalty Kill. A penalty kill is essentially the opposite of a power play. When one of their players commits a penalty and is sent to the penalty box, they are on the penalty kill. They have one less skater on the ice than their opponent, giving them an advantage.

(Side note – As the on-ice strategies during a PP and PK are different than during EV, teams often send out specific groups of players in these situations. These groups are referred to collectively as “special teams”)

SH

This stands for Short-Handed. This refers to a state on the ice in which a team is on the penalty kill. It’s called “short-handed” because they have one less skater than their opponent. It’s often used to describe goals scored on the penalty kill, in the acronym SHG, or short-handed goal.

The Statistics

Technically, quite a bit of what I’ve defined already is a statistic or involves statistics, but when we think of hockey stats, people tend to picture less talking about how many goals a player scored and more someone typing code into a spreadsheet or plotting elaborate graphs. What this section covers is the results of that work.

WAR & GAR

These stand for, respectively, Wins Above Replacement and Goals Above Replacement. Now, we know what both wins and goals are already, but what does the “above replacement” part mean? The simplest way to think of it is this – if the player got hurt, who would have to fill in for them? This means that the replacement here is your average unsigned player (a player who is not on any team) or call-up from the minor leagues (a player who typically plays in a lower league who is asked to fill in a place in the major league). There are several different methods of calculating this, but the basic rule is that the higher, the better. It’s important to think about how the average player should compare to their minor league/unsigned counterparts. If they’re only 5 or 10% better, they’re probably not very good at their job. So, most skilled players should be significantly above that.

Plus/Minus

Usually written as +/-, this is one of the most commonly cited statistics in hockey. It essentially represents their offensive ability versus that of their opponent. For every goal scored by their team while they’re on the ice (provided that goal is not scored on the power play), a player’s +/- is increased by one. For every goal scored by the opponent while a player is on the ice (providing the that goal is not scored on the opponent’s power play), a player’s +/- is decreased by one. However, it’s not as useful as it seems for measuring a player’s individual ability. If the other skaters he’s on the ice with are terrible, his +/- is going to suffer from their mistakes, and vice versa – if they’re great, he’ll be boosted by their talent. That said, it’s a great at-a-glance statistic and useful to understand.

X/60

This represents the amount of a certain statistic – often goals or assists – that occurs per hour of ice time, on average. For example, if a player averages 10 minutes on ice per game and one goal per game, we can see that they average one goal per 10 minutes or six goals per 60. This would make their G/60 equal to 6.

X/GP

This is a similar stat to X/60, but instead of averaging per hour of ice time, it’s per game. So, if a player plays for two games, scoring one goal in the first game and three in the second game, we can see that they score four goals per two games or two goals per game. This would make their G/GP equal to two.

SH%

This stands for shooting percentage and is a measure of how many of a player’s shots on goal actually make it into the net. For example, if a player has 100 shots on goal but only five goals, then their SH% is 5%.

xG

The little x in this stat stands for expected. In this case, it refers to expected goals, but it pops up occasionally in other places as well. What the ‘expected’ actually means is the chance that a goal will be scored, given the positioning of the shot. In essence, it addresses the fact that all shots are not created equal. We can see this intuitively – trying to score from right in front of the net is easier than from the other side of the ice, for example. What xG measures is essentially the quality of shots a player is taking. Even if one player has ten shots and another has only 5, the first player could have less xG than the second if the shots they’re taking are from worse places.

GAA

Most of our other stats have been primarily useful for skaters, but this is our first of the goalie stats. It stands for Goals Against Average and represents the average number of goals a goaltender allows per 60 minutes. So a GAA of 1.00 (they’re usually written with two decimal points) would mean that a goaltender lets in an average of only one goal per 60-minute game. A good GAA in the NHL is between 2.00 and 2.70, but the quality of the defense in front of a goalie and the number of games a goalie plays can dramatically affect these numbers.

SV%

Another goalie stat! This stands for Save Percentage and is a representation of the amount of SOG a goalie saves, as opposed to allowing in the net. This stat is usually expressed as a three-digit decimal. So, if a goalie faces 100 shots and saves 95 of them, they’ll have a SV% of .950 – and given that the average NHL goalie has an SV% of around .910, that’s not a bad number.

GSAA

This stands for Goals Saved Above Average. This statistic takes the league’s average save percentage, applies it to the number of SOG a goalie faced, and figures out how many goals the average goalie would have let in. So, if the league average SV% was 0.500, and a goalie faced ten shots, the average goalie would have let in five goals. It then looks at the number of goals that a goalie actually lets in and compares. So, if our goalie only let in one goal, they would’ve saved four goals above average – so their GSAA would be 4.00 (again, typically expressed with two decimal places).

GSAx

There’s that little x again! Our final goalie stat, this one, stands for Goals Saved Above Expected. It’s easy to confuse with GSAA, especially since it seems like they mean the same thing. However, if we look back at xG, we can see that the word “expected” here actually refers to shot quality. So, this statistic takes into account how difficult it would be for a goalie to save the shots they faced, in addition to whether or not they made the save.

That’s all the goalies for now, but our last pair of stats are possibly some of the most widely discussed – and least widely explained – in hockey.

Corsi

Sometimes called “SAT,” this refers to any shot attempt – so not just things counted as SOG – outside of a shootout. Obviously, this is more encompassing than SOG – if a player tries to shoot but hits the crossbar, that wouldn’t be encompassed in SOG, but it would in Corsi.

Fenwick

Fenwick measures the same thing as Corsi, but it doesn’t include blocked shots – shots that a defender gets in front of before it’s able to make it to the net.

Both of these stats can help give a broader view of a player’s overall offensive capabilities than more discrete measurements like goals or SOG.

Wrapping Up

Obviously, this glossary doesn’t cover every term that could possibly come up in the analytics world, or the hockey world in general, but for the vast majority of hockey fans who want to sometimes know what the numbers guys are talking about, but aren’t necessarily ready to get into coding stat visualizations, this should provide an overview of some of the most common acronyms and phrases that get tossed around. As always, critical thinking and consideration are the most important ingredients in proper statistic analysis, so remember to check back in – we’re always updating and learning new things.