Maintaining possession of the puck at the blue line (carrying or passing the puck across the line) means a team will generate more than twice as much offense as playing dump and chase.
ZE AND SCORING CHANCES
(June 20, 2012)
It looks like dumping the puck is a big tactical error if there is any other option
A player’s Fenwick score (the team’s shot differential with them on the ice) seemed to be largely determined by their performance in the neutral zone
HOW IMPORTANT IS NZ PLAY
It appears that how a team gets the puck into the zone is as important as how often they do it. Maintaining possession of the puck at the blue line (carrying or passing the puck across the line) means a team will generate more than twice as much offense as playing dump and chase.
It may still be true that some players have skills that help the team get more shots per zone entry, but at the end of a year we can't reliably tell which players those are -- we know who did well in the offensive zone this year, but don't have strong reason to believe they'll do well in the offensive zone again next year.
The neutral zone is a different story. The split-half reliability there is 0.44, high enough that we can be 97% sure that this is a real correlation and not just random results. Given a half-season of neutral zone data, we can make a decent guess at what will happen in the other half-season.
How important is neutral zone play?
The neutral zone score alone explains twice as much of the spread in shot differential as the offensive zone score does, and ten times as much as the defensive zone score does.
At least for this one team, neutral zone performance is the major driver of overall shot differential, which in turn drives results.
MEASURING PUCK POSSESSION
nearly 2/3 of the game is spent in transition. That makes the ability to play in the neutral zone extremely important.
zone entries. It makes sense that what happens in the neutral zone is so important because most of the game is played either in or moving into it.
If each team spends 1/6 of the game defending the defensive zone, 1/6 attacking in the offensive zone, and 2/3 of the game fighting over who gets the next zone entry, then that helps explain why neutral zone performance would turn out to be more important than OZ or DZ performance even though it’s farther removed from the actual outcome.
EVALUATING NZ PLAY
the amount of shots that resulted from each zone entry was on average dependent not upon what players were on the ice for the zone entry but rather whether the zone entry was made with control (by carrying in the puck or passing it to a player cutting into the zone) or without control (by a dump or tip in). In other words, it didn’t matter much if it was Sean Couturier or [insert flyers 4th liner here] entering the zone – what mattered was HOW the puck was brought in
Several of the things we previously attributed to offensive and defensive play – shots on goal, shots, even goals to a certain extent – are driven in large part not by offensive or defensive play, but by NEUTRAL ZONE play.
This is not to say neutral zone play is everything of course – you still need goal scorers
The main point here is that neutral zone play seems to be incredibly important toward winning hockey games,
USING ZE DATA TO SEPARATE OZ, DZ, NZ PERFORMANCE
(Unfinished – pdf)
The biggest driver of Corsi is neutral zone play.
Breaking the game into OZ, DZ, and NZ possessions permits detailed understanding of what drives success.
Shot differential derives almost entirely from NZ play.
OZ success is largely a result of Shot Quality effects.
ZONE STARTS AND NZ PERFORMANCE
Oddly, the more offensive zone faceoffs you take, the lower your Neutral Zone #s – the reason for this is that if you start a shift on an offensive zone faceoff, when the puck goes back to the neutral zone it’s now going the other direction and is likely heading into your own zone.
However, despite the last two paragraphs, it appears that the effect is minor.
IMPORTANCE OF NZ PLAY VS OZ AND DZ
First:
It appears that how a team gets the puck into the zone is as important as how often they do it.
Second:
The net result here: our surprising results in the offensive and defensive zones appear to be based on a not-particularly-reproducible metric.
we know who did well in the offensive zone this year, but don’t have strong reason to believe they’ll do well in the offensive zone again next year.
The neutral zone is a different story. The split-half reliability there is 0.44, high enough that we can be 97% sure that this is a real correlation and not just random results. Given a half-season of neutral zone data, we can make a decent guess at what will happen in the other half-season.
possession is near completely driven by neutral zone play, and that offensive and defensive zone play is mainly dictated by the play in the neutral zone.
Conclusion:
Could be that certain systems lend themselves to consistent play in one or more zones more than others.
ZE DATA AND DRIVERS OF SHOT DIFFERENTIAL
Advancing the puck forward more often than the opponents do (so they get more entries) and keeping control of it as they enter the zone (rather than dumping it in) are major drivers of outshooting the opponent.
The strongest individual contribution to shot differential appears to be what percentage of the time a player’s zone entries are by carrying the puck in rather than dumping it in.
ZONE ENTRY AND SHOT DIFFERENTIAL
Zone entries are a major driver of shot differential at even strength.
It’s one of our strongest measures of an individual’s contribution to puck possession.
There are four places where they generate an edge over their opponents:
· The Kings get more shots than average when they carry the puck in
· Their opponents get fewer shots than average on their carry-ins
· The Kings get more than half of the entries
· The Kings get a lot more offensive zone faceoffs than their opponents
Shots Per Entry:
There’s mixed evidence on how repeatable a player’s shots per entry are. If I had to guess, I’d guess that there are modest differences in talent that are largely swamped by random variance over tens of games.
Given that there isn’t compelling evidence that top line forwards generate more shots per entry than enforcers, I’m hard-pressed to attribute this to a difference of skill.
Extra Possessions:
The extra shots per possession are a sizable chunk of the Kings’ edge, but the majority of it comes from getting extra offensive zone possessions
But the largest share of the Kings’ shot differential comes from generating more possessions with their neutral zone play
Zone Exits:
When a team exited the zone with possession of the puck, carrying or passing it out, the next zone entry was at the other end of the ice 74 percent of the time. For all other zone exits, play shifted to the other end only 48 percent of the time.
Clean zone exits aren’t the reason the Kings get more offensive zone possessions than their opponents.
NZ Play:
The effect here is much larger than the effect of the zone exits; whereas the extra exits with possession produced roughly a 50.3-49.7 advantage in number of possessions, this zone shift factor by itself would produce a 52-48 edge.
But the largest chunk of their possession advantage comes from simply winning the neutral zone
HOW REPEATABLE IS ZONE PERFORMANCE (TEAM LEVEL)
This suggests to me there’s a heavy coaching influence going on here.
Neutral Zone Play is certainly incredibly important. But teams have seemed to succeed via offensive and defensive zone success WITHOUT neutral zone success, which suggests it may not be AS important as Eric’s initial work suggested.
REPEATABILITY OF OZ, DZ, NZ PERFORMANCE ON INDIVIDUAL LEVEL
Certain teams may be able to consistently get above average offensive or defensive zone performance, like the Sharks, even if individuals might not be consistently above average relative to their teams.
NZ SCORE AND NZ REL SCORE
The best current metric for accessing neutral zone play is “neutral zone score” (NZ score)
Because NZ score (like Corsi For% and Fenwick For%) is derived from on-ice data, it has limited value when comparing players from different teams. To allow for better player to player analysis a “NZ score relative” metric can be used.
NZ Score relative is determined by comparing the team’s NZ score when the player is on the ice, to the team’s NZ score when the player is not on the ice. It is a measure of how the team performs in the neutral zone with a given player on the ice relative to how they do without him.
WHAT IS DRIVING RESULTS (SKILL, SYSTEMS, RANDOMNESS)
Teams do seem to have control over their results in the offensive and defensive zone, as well as the neutral zone.
Teams that are good in the offensive, defensive, or neutral zones are likely to remain good at play in those zones.
Individual Offensive and Defensive Zone Performance, at least in terms of driving possession, is pretty much completely random over a half season. In other words individual players do not demonstrate skill over a half season sample in creating more shots than the average player per type of entry in the offensive zone (or preventing more shots in the defensive zone).
Individual players show some control over their teams’ performance in the neutral zone, but not over their teams’ ability to get/prevent shots on net in the offensive/defensive zones. That individual player who is weak in the neutral zone but seems to get loose pucks in the other two zones probably isn’t going to keep making up for his bad neutral zone play in that fashion for long.
That said, on a team level, Eric’s initial findings are NOT correct. Teams do have the ability to drive possession in the offensive and defensive zone. This suggests highly that systems and coaches matter, and that a team can survive without winning the neutral zone
WHY NZ IS MORE IMPORTANT THAN YOU THINK
(Sep 2015)
It’s not what happens in the offensive zone that has the biggest impact, though. Rather, teams who excel in the neutral zone are creating the most opportunities.
How a team enters or defends the zone has a notable impact on its Corsi or Fenwick because a player that carries the puck in with control creates more than twice as many shot attempts compared to those who dump the puck in and chase it.
· Defense drives the bus: For almost every metric, the defensive version was more indicative than the offensive. What that likely means is that the neutral zone is system driven.
The best teams weren’t always the ones that won the neutral zone, they were the ones who were most effective on each entry for and against. Overall it seems as if shots per entry are more important to a team than getting entries,
WHY NZ STATISTICS MATTER
First, we found that a controlled zone entry results in more than twice as many unblocked shot attempts (fenwicks) as an uncontrolled entry.
Second we were able to identify that some players are particularly effective at entering the zone with control than others and that some players take bigger roles at trying to make zone entries than others
For individual players, only performance in the neutral zone was repeatable.
Team Performance in the offensive and defensive zone over a half season is in fact repeatable.
This suggests that the neutral zone is an extremely important feature of an NHL game and that stats measuring it are similarly important.
Players who win the neutral zone battle are more likely to put up good possession #s repeatedly than players who don’t, because performance in the other two zones doesn’t seem to be entirely repeatable.
SHOT GENERATION IN THE NZ
If the attacking team is able to regain possession in the neutral zone, they can either quickly get the puck back into the offensive zone or send the puck back into their own defensive zone for a regroup or controlled breakout.
Most teams prefer to use regroups where the defensemen maintain possession near their defensive zone faceoff circles while the forwards build up speed and create separation from checking players to provide passing options for the zone entry.
Occasionally, due to heavy pressure from the opponent’s neutral zone forecheck, the defenseman will take the puck and hold it behind his goalie’s net while all of this happens (controlled breakout).
ENTRY GENERATION AND SUPPRESSION
Gaining zone entries and preventing them are two unrelated skills.
In general, shot generation and shot suppression are mostly independent”. In other words, the players that generate the most shots for their team do not necessarily prevent shots against.
Results: The best offense is just a good offense, the best defense is just a good defense
There is no relationship between generating entries for and preventing entries against
Generating and preventing entries are two separate skillsets in the neutral zone, and looking at each one separately can help understand how a player produces results.
INFORMED NZ DECISIONS (IMPORTANCE OF PASSING)
Whether a team enters with possession or not, or if you’re just looking at the team’s total number of entries/60, these numbers are repeatable and not due to chance.
When predicting shot rates, you’ll notice that a team’s shot rate is still the best predictor of its future shot rate. However, I was surprised to see how LOW the Controlled Entry/60 metric predicted shots/60.
Controlled entry rates predict future goals almost as well as shots do,
What really stands out is how predictive a team’s total entries are at predicting future goals, significantly better than a team’s shot rates.
· All types of entries are repeatable
· Controlled entries are significantly more predictive than dump-ins
· A team’s total rate of entries appears to predict out-of-sample goals better than shot rates
A perfect play in transition: one that attacks the open ice and allows teammates to come in behind for quality chances.
The rate at which teams make passes into the zone on controlled entries, as well as sustained passing sequences in transition, are repeatable and not due to randomness
it’s also significantly more effective at predicting future goals than shot or entry rates.
Passing plays in transition are significantly better at predicting future goals than shot rates or entry rates that we explored at the outset of this piece.
Conclusion:
How you enter the zone certainly matters, but the action immediately following your zone entry appears to matter significantly more.
TRAITS OF SUCCESSFUL NZ TEAMS
(2016)
you’re going to carry every time your opponent is sucking at defense, and when your opponent is sucking at defense, you’re going to have better chances to score
Support Through The NZ:
You’re best coming up the ice together, and I mean together; all three forwards being on the same half of the ice isn’t a terrible thing.
Use Short Passes:
A five-foot pass under a D-man’s triangle as players cross the blue line is instant zone access with possession.
The opposing center is trying to stay above yours, opposing wingers are trying to force the puck to the wall, and they’re trying to get pressure before the red line.
If a group can come through the middle with at least a couple of players flying, they can take the defensive team out of Tactical Planning Mode, and thrust them into Holy Shit Panic Mode. Teams have trouble playing “their game” against speed.
The basic concepts are simple – if you support one another, move the puck early and often, and get those feet movin’, you’ll have a lot more success at gaining the opposing zone with possession of the puck.
NZ PLAYING STYLES
Perhaps the biggest question in neutral zone playing styles is the importance of coaching and systems compared to individual player’s natural talent and preferences. How much is the decision to carry or dump the puck influenced by instructions from the bench?
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