Exit Types Don’t Affect Entry Quality (Much)

Last time, we saw that a team exiting its defensive zone with possession is much more likely to enter their offensive zone. Do the advantages end there, or do possession exits also improve the quality of zone entrances? Perhaps leaving the defensive zone with possession makes it easier to keep possession as they enter the offensive zone, and that leads to more shots per entry. Maybe pass-outs create space for more passes in the offensive zone, which improves shot quality.

It turns out that there is not much of a difference in entry quality by exit type; exiting with possession makes it more likely to gain the offensive zone, but the advantages quickly dissipate. That said, there are some interesting variations in how those zone entries play out. The differences are small enough that they could be random chance, but it’s worth taking stock of what we know with the data we have.

Exit Type Influences Entry Type a Bit

As we’ve discussed before, carrying the puck into the zone is better than dumping it in because entries with possession are more likely to get shot attempts. That continues to hold true for our zone entry sample: carry-ins average 0.6 shots per entry while dump-ins had 0.3.

So if a certain type of zone exit leads to more carry-ins, then it’s also leading to higher quality zone entries. We do see some variation when we look at the zone exits. Here’s what carry-in percentage looks like for the 47,000 pass-outs, 27,000 carry-outs, and 15,00 dump-outs that led to an entry:

Carry In Share by Exit Type

When a transition gets the puck from the defensive zone to the offensive one, it’s more likely to be a carry-in if it the breakout was started with a pass than with a dump-out. This difference is statistically significant. Carry-outs fall in between. Note that this is distinct from the last post’s findings that possession exits lead to entry success; now we see that looking only at the successes, possession gets better successes. We also see some separation between passes and carries for the first time. I suspect that here is where we’re seeing the advantages of passing the puck in the neutral zone to open up space for an attack.

But Exit Type May Also Influence Shots Per Entry in the Opposite Direction

Pass-outs lead to more carry-ins, and carry-ins lead to more shots per entry, so pass-outs should have more shots per entry, right? Not as much as you’d think.

Shots per Entry by Exit Type

Entries after pass-outs do get more shots per entry, but the gap is much smaller. Furthermore, carry-outs actually do a bit worse than dump-outs. There does not seem to be much variation in entry quality at all.

How can this be? The additional carry-ins from possession exits get mitigated by an interesting quirk: breakouts that use dumps for both the zone exit and zone entry do a bit better than other types of dump-ins.

Shots Per Carry and Dump by Exit Type

These dump-out-dump-in plays are good enough that they balance out the drop in possession carry-ins. This could be a systemic result: maybe teams that play dump and chase at all times have structures to succeed. But I’m skeptical. These results could also be reflecting a particular type of defensive play from the opposing team that forces dump-ins at the expense of weakness in the zone; one could imagine an aggressive defense standing up players in the neutral zone: it works by preventing entries, but results in less defensive coverage when teams do get through. Finally, the difference is small enough that it could just be a fluke.

So, what should we do with this information? In all honesty, probably not much. The differences here are pretty small and could be quirks of this data that will evaporate as the sample grows. I would be interested in investigations of whether dump-out-dump-in plays have a structure that explains their slight boost in success, but this is a pretty minor point.

Rather, I think it may be best to determine that this investigation turned up negative results: if a zone entry occurs, its quality probably doesn’t have much to do with the zone exit that preceded it. Therefore, the crucial portion of a zone exit is ensuring that there’s any zone entry at all. Once the team breaking out is in a full-on attack into the offensive zone, it’s a whole new game.

If anything, the larger carry-in percentage for pass-outs give further weight to the argument that pass-outs are the best possible zone exit. This is particularly appealing because it seems like a type that can be improved through coaching; while carry-outs are largely dependent on the player’s skating and stick handling skill, pass-outs can be encouraged with a structured breakout system that encourages multiple anticipated passing options as soon as possession is obtained.

Finally, here’s Nathan MacKinnon showing that a carry-out can lead to a carry-in, but it takes a little bit more to turn it into a goal:

Post 3 MacKinnon Gif.gif

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