Why Possession is the Key to Zone Exits

If there’s anything you know from neutral zone analytics, it’s probably this: carry-in zone entries are better than dump-ins. In the linked piece, Eric Tulsky finds that “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”.

But what about zone exits? Is possession equally important there? Work by Jen Lute Costello suggests that it is, but her data was limited to one playoff series. Today, I’ll expand on her work to show that maintaining possession is crucial for successful zone exits, and breakouts should be structured with this in mind.

For this study, I’m relying on Corey Sznajder’s dataset discussed in my first post. When I downloaded data for this analysis, he had tracked roughly half of the games from the 2016-2017 and 2017-2018 seasons. While some teams are more extensively covered than others, they almost all have more than 50 games covered (VGK has 27 because it is only in one season, and VAN has 49). This dataset includes an astounding 230,000 individually tracked zone exits with six different result types. Here is how many of each type we have, grouped into whether the exit failed, succeeded without possession, or succeeded with possession:

total exits tracked

Icing, carry-out, and pass-out are straightforward. “No exit” means the player attempted to exit the zone but failed, and the opponent regained the puck in the offensive zone. This is essentially a turnover. Dump-outs are split based on whether or not the team exiting the zone regained the puck in the neutral zone after dumping it out.

You’ll notice I split exits with and without possession. Traditionally, this isn’t done: a successful zone exit is one that gets out of the zone: if the puck crosses the blue line and the attacking team is forced to retreat, the zone exit worked. That definition is reasonable, but I think it lets teams off the hook. Every fan has seen a defenseman lob the puck into the neutral zone only to have the opposition pick it up and bring it right back into the zone. Often, it happens so quickly that the defense can’t even make a change. I think these cases are similar to blocking shots (and Kent Wilson’s famous analogy): better than not doing anything, but not actually a long-term success. It delays a bad event rather than preventing it.

Instead, better zone exit criteria should be based on the next zone entry. The goal of a zone exit is to take the puck from the defensive zone and start moving it to the offensive zone. Without gaining the next entry, a zone exit is a small victory in an overall failure. If you don’t believe me, promise a loved one you’ll come visit, don’t show up, and when they react, explain that you deserve partial credit because you successfully left your house.

Granted, there are other pieces between the zone exit and the next entry. If someone makes a great zone exit but then turns it over in the neutral zone, I count this as a failed zone exit. This is suboptimal, but I think it is a lesser evil than giving credit to a weak dump-out that hands the puck back to the opposition. We ought to be measuring how well the attempted zone exit starts a real breakout.

So, with that harsher criteria, what type of zone exits are more successful, i.e. lead to a subsequent zone entry?

exit results

Carry-outs and pass-outs are both extremely successful, working almost nine times out of ten. On the other hand, dump-outs are consistently terrible, working just one in five times. The size of the gap between exit types is enormous, and a team can dramatically improve their performance if they are able to exit with possession more often.

I’m actually a bit surprised at just how large the gap is here. A carry or pass-out is almost 4 times as likely to work as a dump-out. I’m also surprised that carry-outs were a bit more successful than passes. I’d have guessed that passes would be better because they stretch the play and give the player with the puck more room. Now, my post-hoc explanation is that the pass’s benefit is counterbalanced by the extra challenge of receiving it cleanly.

What is it about carries and passes that make them better than dump-outs? Possession. We can tell because the data also shows whether or not each dump-out is recovered: when a team dumps the puck out and then regains it in the neutral zone; they have an 89% chance of getting the next entry. That’s right, almost identical to any other type of exit.

It is crucial to understand the implications of this result. The key differentiator for zone exit success is possession and not some other difference between dump-outs and other exits. The key problem with dump-outs is that they voluntarily give up possession. As soon as that disadvantage is mitigated, they are just as successful as any other exit. Possession is the key explainer.

It’s easy to say that players should exit the zone with possession more often, but perhaps they have valid reasons not to. What if players already know this, but they dump the puck out when they are in a tough situation and have no other choice? Maybe if they forced a possession exit more often, success rates would drop and they’d fail to get out of the zone entirely?

We can’t solve this conclusively without better data about the zone exit situation and zone exit failures, but the evidence we have suggests that this is not the case. For one, we do have data on whether the exit faced forecheck pressure. I’ll explore this more in a later post, but success rates for each exit type barely drop at all when there is pressure. This indicates that the success of possession exits is not just indicative of the situation’s easiness.

Furthermore, the success rate disparity is so huge that on the margin, carrying the puck out is the better decision. I fully acknowledge that the perfectly optimal solution will not be 100% carry and pass-outs, but it’s somewhere between that and the status quo.

Finally, the success disparity makes it critical that coaches design defensive coverage and breakouts in ways to avoid “desperation dump-outs” and provide options for possession exits instead. In Arik Parnass’ work on power-plays, he advocated for “structured creativity”, where players were empowered to make decisions within a structure that gave them multiple default options. Breakouts may not be the best time for creativity, but that type of structure would be enormously beneficial. Establish a breakout structure where the player who first gets the puck – and is likely being pressured to make a play quickly – knows exactly the couple of places to look to make a strong play.

In my next post, I’ll talk about whether the benefits of zone exit possession extend throughout the rest of the offensive opportunity. For now, here’s a video of Nick Leddy showing what you can do when you regain neutral zone possession after a dump out goes awry:

Leddy Gif

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