Puck Possession, A Potentially Misleading Principle

Over the years, analytics in hockey have grown and evolved. Shot metrics and measures that provide context to them have become part of the standard toolbox used by many inside and outside of NHL offices. The principle of puck possession, while known to the hockey world since time immemorial, has taken on a whole new level of importance with shot metrics gaining in popularity.

Shot metrics were initially* explored in an effort to discover a decent proxy for time of possession in hockey. Much like you see in other sports such as football, people wanted to get a better handle on quantifying how often and for how long specific teams had the puck as opposed to playing defense, i.e. time of possession. The thought process here was fairly logical. Because the objective in hockey is to score goals, having the puck is better than not having it.

Shot metrics, such as Shots On Goal, Shot Attempts (Missed, Blocked, On Goal) and Unblocked Shot Attempts (Missed, On Goal), were explored as ways to potentially find measures that could reproduce time of possession without necessitating a person with a stop watch timing every possession in every NHL game. As it happened, a strong correlation was found between those metrics, particularly Unblocked Shot Attempts, over the course of the regular season, and success, namely landing a spot in postseason play. That correlation provided confidence in the reasonable reliance on these metrics as tools to measure the strength of teams.

Teams which show well in these metrics are often called “strong possession” teams. “Puck possession” has become a commonly used term and is the generally accepted phrase for the modern approach to achieving success in hockey. “Puck possession” is a bit of a misnomer though in its current usage.

Teams spending long periods of time in the offensive zone, or possessing the puck, is good right? Not necessarily. It’s certainly better than constantly being hemmed into the defensive zone, of course; however, simply having the puck in the offensive zone (passing, running the cycle, i.e. what many term as “puck possession”) is not what has been established as having a high correlation to success. Shot generation (creating shots toward the net) and shot suppression (preventing shots toward the net) are actually the metrics that have been linked to success.

Regardless of how long teams spend in the offensive zone, if they are passing and failing to generate shots, they are not exhibiting the hallmarks of success because they are not generating shots toward the net. If you try to visualize this, these long periods of possession often resemble a power play. The attacking team gains the offensive zone, establishes a cycle and passes the puck numerous times looking for a “perfect shot” instead of creating multiple shot attempts during the possession.

The common thinking that may be leading some teams to this is that a shot toward the net creates the opportunity not only for a goal, but for a rebound or miss that could be collected by the defending team and thus necessitate getting back on defense themselves. It may be that some coaches feel long periods of possession, despite a lack of shot generation, are a form of shot suppression or at the very least, in keeping with the principle of puck possession. Technically, this is true; however, the teams using this form of possession often seem to be lacking in solid defensive systems.

Shot suppression is not achieved simply by keeping the puck out of your defensive zone by holding it in the offensive zone. Every team in existence has to get back on defense. Denying the attacking team’s entry to the offensive zone, aggressive backchecking, sound and well executed breakout plans from the defensive zone and the like are far more effective in achieving shot suppression than trying to keep the puck in the offensive zone for extended periods of time. These strategies are also more effective for shot generation because they are all ways to help the team get back on the offensive attack using a quick transition.

It is intriguing to think that the quest for a good proxy for time of possession has actually led to a finding that success is not really a matter of time of possession, but a matter of shot generation and suppression, which are far more complex than simply being in the right zone of the ice.

Teams like the Colorado Avalanche seem to understand the long held tenet of “puck possession”, but have attempted to adhere to that principle using the possession time strategy as opposed to the shot generation/suppression strategy. The Avalanche are not the only example of this in the NHL to be certain. It probably isn’t a coincidence that they use systems which, on their surface, seem in keeping with the principle of puck possession, but which, upon closer inspection, display a failure to grasp the true meaning of the principle.

As the decision-makers are afforded a more informed, nuanced approach to the principle of puck possession through the adoption of shot based analytics, it will be interesting to see the changes made to their strategies for adhering to that principle.

*Shot metrics were explored for several reasons initially, not simply for time of possession. Work was done to see what meaning shot metrics and scoring chances had within the game of hockey by bloggers in the Edmonton Oilers fan base after learning that the team tracked scoring chances. Thanks to Garret Hohl for mentioning this to me so I could edit and include this for the sake of accuracy.

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Keep the Conversation Going

Recently, I wrote about how issues regarding sexual assault, abuse and violence are tough to grapple with as sports fans and received an overwhelming response from men and women saying they were feeling many of the same things. Yesterday I posted a few things on Twitter regarding sexual assault statistics and applied them to hockey. I have included those below.

I make a lot of space for hockey in my life and so I thought that may help me and other fans get a better handle on this overwhelming societal issue. Many of the responses I got completely ignored the societal issue and instead were filled with accusations that I was holding one sports star out as a “sacrifice to the movement” despite the fact that I did not refer to him in any of those posts.

It seems like many are having trouble seeing the difference between the necessity of reevaluating the way we as a society view sexual assault, abuse and violence, and the guilt or innocence of one sports star. The discussion so many people have been having this summer and for years prior is about centering victims and tearing down the barriers that so often keep them suffering in silence. Continue reading

Competitive Advantage: Putting 2 and 2 Together

With expansion plans in the works, the NHL and the teams that comprise it are under pressure to increase revenue. Sports are entertainment and in the entertainment business, fun is money. It’s not rocket science to link a rise in the number of fans to a rise in the amount of money coming in. Every team in the NHL wants to win. Even the teams that have been rumored to have tanked for attractive draft picks want to win, albeit just a little bit farther in the future. All things considered, winning, or even the hope of winning, is good for the bottom line.

Hockey teams are businesses comprised of human beings. Most human beings, like it or not, allow their feelings about a person to dictate how much latitude and gratitude they are willing to give. If a player is well liked, works hard and listens to the coach, the coach will often like that player. That player will get more latitude for the mistakes he makes and more gratitude when he does something well.

The coach’s feelings about a player will often direct his eye away from the player’s deficiencies and toward his strengths. This works the opposite way as well. If the coach is not very fond of a player for whatever reason (preconceived ideas of the player’s skill level, work ethic, personality, etc…), he is more likely to see that player’s mistakes or shortcomings than his talents. This is often referred to as “confirmation bias” and it is just basic human nature inside and outside of sports.

The problem with this part of human nature is that it leads to decisions based on skewed information. Looking at this through the lens of hockey as a business, this can have a negative impact on the bottom line. The business of sports is about gaining a competitive advantage and confirmation bias often hinders this. Gaining a competitive advantage when management and coaching are not on the same page can be a monumental chore.

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Using Player Skill Sets To Gain An Advantage: 1-3-1 Neutral Zone Forecheck

The race to find a competitive advantage in hockey is reaching unprecedented heights. One of those advantages is finding a reliable way to identify a player’s unique skill set. Once you know what a player’s strengths and weaknesses are, you can more efficiently maximize his strengths and insulate his weaknesses.

Knowledge of a player’s skill set can help inform coaching decisions and lead to tangible results on the ice. The following discussion on the 1-3-1 Neutral Zone Forecheck provides an example of how this information can be used.

A quick introduction for those who may not be as well-versed:

The Neutral Zone Forecheck is the name given to a variety of formations used to defend against the team’s opponent gaining the offensive zone. This is not to be confused with the Offensive Zone Forecheck, which is any number of formations used to regain possession of the puck after entering the offensive zone.

When the opponent has the puck and is regrouping or setting up a controlled breakout in their own defensive zone, the defending team has time to get their players set up to defend against the entry. The 1-3-1 Neutral Zone Forecheck often looks like this initially:

T.B FORECHECK

1-3-1 NEUTRAL ZONE FORECHECK, INITIAL FORMATION

F1 is the first line of defense. This is usually a forward who is a very agile skater and skilled at creating turnovers. F2 and F3 set up in the wide lanes. D1 and D2 position themselves nearly parallel to the faceoff dots on the neutral side of their own blue line.

There are two options with the 1-3-1 for the D1 and D2 assignments. The first option allows the defensemen to make the decision as to which of them will move up to join the forwards thus creating the 1-3-1 formation. This is dependent upon which side of the ice the puck carrier is on. Obviously, exercising this option requires a lot of practice at reading the oncoming attack and clear communication between the defensemen.

The second option is to decide in advance which defenseman will play up and which will drop back. There’s less opportunity for miscommunication with this method since everyone knows his assignment to begin with.  F1’s responsibilities change a bit from many other NZ forecheck formations. F1 is often very limited in how far he is able to move around to pressure the breakout or regroup; however, in the 1-3-1 formation, F1 can pretty much do as he pleases so long as he is pressuring the puck carrier to make a poor or ill-advised pass.

Below is an example of the movement allowed. F1 chases the puck carrier out from behind the net. The puck carrier can try to skate higher up in the zone to make a shorter pass, but he will do so under heavy pressure from F1, thus increasing the likelihood of a turnover. The puck carrier could also pass to a waiting forward.

T.B FORECHECK 1 3 1

1-3-1 NEUTRAL ZONE FORECHECK

The illustration above shows the motion of the various players as the puck is moved higher up in the zone. The forward on the strong side, in our example, F3, moves up to pressure the puck carrier. D1 is the defenseman playing up in this formation. He will help pressure the entry by taking away any passes and taking up space in the middle of the ice. The forward on the other side, F2, will drop back a bit while continuing to take up space and disrupt the entry. D2 will read the play as it advances and essentially hold down the fort in the defensive zone. Anything that gets through the neutral zone is his responsibility, at least initially.

The point of this type of forecheck is to force the puck carrier to make a long pass since there is, ideally, no room to carry the puck through the neutral zone. Teams will often counter this by using a hard pass into the neutral zone that one of the waiting forwards will tip into the offensive zone. Essentially, this is a dump in type of zone entry, because the puck will shoot into the offensive zone will velocity and the attacking team will go into their forecheck formation to try to recover the puck.

If teams use the second option in the 1-3-1, i.e. determining in advance which defenseman will play up and which one will drop back, there is a good opportunity to maximize the skill set of each of the defensemen. The defenseman playing up should be the player who is more crafty in using his positioning, skating and/or his stick to create turnovers when defending the zone entry. This is an excellent time to knock the puck loose, because the defending team has at least three players in the neutral zone that can try to recover the puck and go on the attack.

The defenseman playing back should be the player who is the more skilled passer of the pairing. If the puck gets dumped into the offensive zone, he obviously has the first opportunity to get to it. Once he has the puck on his stick, he can read the coverage and make a good pass to targets high in his defensive zone or in the neutral zone. The more accurate his pass, the more likely his team will be able to go on the offensive attack.

Using the more fluid option of having the defensemen switch up who is playing where diminishes the ability to maximize the individual skill sets of the defensemen. Even at the NHL level, it is not likely that each defensive pairing is comprised of players equally skilled at breaking up entries by creating turnovers with their sticks, skating, reading coverage and passing. Defensemen are not in fact interchangeable in these roles if the goal is to get the most from each player’s unique talents.

Generating offense is heavily reliant upon the defense. The manner in which the team exits the defensive zone has a huge impact upon whether or not they gain the offensive zone. Using the better passing defenseman as the drop back defenseman in the 1-3-1 gives the team an edge in turning the play in the opposite direction.

Stanley Cup Final Systems Look: Gaining the Offensive Zone

Zone entries are very important to the efficacy of a team’s offense. It is commonly held that carrying the puck into the zone leads to more shots than dumping the puck in and trying to recover possession. While I have tracked the zone entries for the Chicago Blackhawks as the season has worn on, I have not done so for the Tampa Bay Lightning. Because of that, I thought we could look at the systems each team uses to gain the offensive zone and discuss the players to keep an eye on in this part of the game instead of going too heavily into zone entry statistics.

BREAKOUTS

Breakouts are the plans a team uses to get the puck from the defensive zone into the offensive zone. This happens in two distinct situations. The first is when the opponent has been on the offensive attack and the defending team works to regain possession and quickly move the puck out of the zone. The second occurs when the defending team regains possession of the puck, but holds it behind the net to allow for line changes prior to starting out of the zone. This second situation is referred to as a “controlled breakout”.

Breakouts that happen on the fly (the first situation referenced above) have a fairly standard set of plays used by teams throughout not only the NHL, but hockey in general. When you hear the defenseman without the puck yelling “UP” or “WHEEL” (among others) to his defense partner, he is calling out the breakout play to be used. D2’s read of the pressure from the attacking team is vital to executing the breakout. D1 is often gathering the puck with an opposing player all over him or at least right on his heels so he does not have much time to look around.  Continue reading

Zone Entries, Exits, Targets CHI vs ANA

The following data was tracked from Game 5 of the Anaheim Ducks vs. Chicago Blackhawks series. Given that Game 7 is also at Anaheim, this information may be useful for insights into how the matchups on Anaheim’s home ice affected the teams’ performances.

*All data herein was tracked by and is the work product of Jennifer Lute Costella.*

PLAYER ID GUIDE

ana chi g5 roster

ZONE ENTRIES – EVEN STRENGTH

The following data is for 5 on 5 play only during Game 5 in Anaheim. Dump ins include chip and chase entries as well as traditional dump ins from the neutral zone. Carry in entries include both entries accomplished by carrying the puck into the offensive zone on your stick as well as a short direct pass from the neutral zone to a player entering the offensive zone. The player making the pass is credited with the carry in for that situation.

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Clearing the Defensive Zone: The Dangers of Dumping the Puck Out

Over the course of the season, I and others have often talked about the importance of defensive zone exits. On numerous occasions, we have debated (on Twitter) the pros and cons of simply getting the puck out of the zone to relieve offensive pressure versus starting a proper breakout play. People often argue that because players are tired at the end of a shift, particularly one where they have been actively defending for an extended period, simply getting the puck out of the zone without icing helps the team.

Ways the puck leaves the defensive zone:

  • Happenstance: a pass from one offensive player to another misses and the puck ends up in the neutral zone causing the attacking team to regroup and restart their attack;
  • Controlled Exit:
    • Carry Out: One of the defending players gains control of the puck and skates it across the blue line;
    • Exit Pass: One of the defending players gains control of the puck and makes a tape to tape pass to a teammate in the neutral zone;
  • Uncontrolled Exit:
    • Dump Out: One of the defending players gains control of the puck and shoots it into the neutral zone:
      • Missing the intended target;
      • Without an intended target, i.e. simply to get the puck out of the defensive zone;
      • To execute a line change.

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Zone Exits & Breakouts: Chicago vs Nashville

Zone Exits and actions taken in the defensive zone are the most intriguing part of microstats to me. I am admittedly a bit obsessed with defensive systems and shot suppression so this is probably not surprising. Defensive zone microstats are key to evaluating players, systems and teams. They can help teams identify areas of weakness or strength in players. In turn, defensive zone microstats can be used to tweak systems to better exploit the strengths of the defensemen and insulate the risks associated with their weaknesses.

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Defensive Targets: CHI vs NSH

While tracking zone entries, I include the defenseman targeted on the entry. I also keep track of whether a forward assisted on defending against the zone entry. This data can help evaluate team and player performance as well as the efficacy of the systems used by the teams. This is particularly true of a team’s neutral zone forecheck, or the system they use to stop the attacking team from entering the zone. Zone targets are heavily dependent upon time on ice, so please keep that in mind while reviewing this information.

Tracking Information:

Targeted D: Defensive player responsible for the side of the ice through which the attacking player tries to enter the zone. This may also be the player pressuring the puck carrier at the blue line or the player filling in for the defensive player on an oddman rush or breakaway.

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Zone Entries: CHI vs NSH Player Breakdown

Now that the team breakdown is complete, we can move on to the player breakdown of the zone entries throughout the Chicago versus Nashville playoff series. Aside from telling you how each of the players fared during the series, I also want to show you some of the possibilities for using the information tracked through microstats (such as zone entries and exits) to evaluate players, line combinations and systems.

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