Save percentage since the 3-on-3 overtime era (2015-16 to today)

[The Panther]

My understanding is that overtime save percentage has no unique aspects in overtime, right? That is, it simply counts as regular save percentage. But surely, the period of 3-on-3 overtime (since October 2015) must have skewed save percentages by some degree...? There must be something like a 50% chance of a goal being scored in the five-minute 3-on-3, compared to probably less than 1 every ten minutes in regular play.

So, I wonder, hasn't 3-on-3 overtime somewhat skewed save percentage of goaltenders, particularly those who lose in a lot of overtimes?

I realize save percentage also doesn't make exceptions for PPs and whatnot, but I just think the chance of a goalie making a typical number of saves in overtime is very, very small.

Has anyone seen any stats that take this into account?

Click to read more...

 

[Doctor No]

Save percentage by regular season period, 2016-17 to present. Any errors in the results are from errors in my underlying data.

Regular Season	Period 1	Period 2	Period 3	Period 4	Total
201617​	0.921	0.909	0.914	0.843	0.913
201718​	0.918	0.907	0.915	0.850	0.912
201819​	0.914	0.906	0.913	0.829	0.910
201920​	0.914	0.906	0.912	0.844	0.910
202021​	0.914	0.906	0.908	0.830	0.908
202122​	0.914	0.902	0.909	0.843	0.907
202223​	0.911	0.898	0.906	0.832	0.904
202324​	0.908	0.899	0.906	0.815	0.903
202425​	0.906	0.898	0.902	0.754	0.900

Save percentage by regular season period (relative to the overall save percentage for the season):

Regular Season	Period 1	Period 2	Period 3	Period 4	Total
201617​	100.8%​	99.5%​	100.0%​	92.3%​	100.0%​
201718​	100.7%​	99.4%​	100.3%​	93.2%​	100.0%​
201819​	100.5%​	99.6%​	100.3%​	91.1%​	100.0%​
201920​	100.5%​	99.6%​	100.2%​	92.7%​	100.0%​
202021​	100.6%​	99.7%​	100.0%​	91.4%​	100.0%​
202122​	100.8%​	99.4%​	100.2%​	93.0%​	100.0%​
202223​	100.8%​	99.4%​	100.3%​	92.1%​	100.0%​
202324​	100.5%​	99.5%​	100.3%​	90.2%​	100.0%​
202425​	100.6%​	99.8%​	100.2%​	83.7%​	100.0%​

 

[Golden_Jet]

Yes save percentage is worse in OT, but save percentage has been dropping overall (Al periods) year by year lately. Some of it do to goalie rule changes, but there are other factors.

 

[morehockeystats]

The save percentage drop is expected because there are more dangerous shots in OT. It'd be interesting to compare XG saved, too.

 

[Namejs]

Yes save percentage is worse in OT, but save percentage has been dropping overall (Al periods) year by year lately. Some of it do to goalie rule changes, but there are other factors.

It has little to do with any rule changes, as the effects would not be gradual or continuous, spanning a decade.

It has more to do with changing dynamics of the game itself, notably more lateral plays in the offensive zone.

Similar to basketball and 3-point shots, this change has been analytics-driven.

The 3-on-3 effect is pretty negligible.

 

[Golden_Jet]

It has little to do with any rule changes, as the effects would not be gradual or continuous, spanning a decade.

It has more to do with changing dynamics of the game itself, notably more lateral plays in the offensive zone.

Similar to basketball and 3-point shots, this change has been analytics-driven.

The 3-on-3 effect is pretty negligible.

The goalie rule changes were also gradual, not all at one off season.
Plus I said that was just one of the reasons.

 

[DJJones]

Expansion teams, OT, pulling goalies early, goalie equipment, calling penalties differently.

Everything is forcing goals to go up. And if anything shots are stable if not going down. Firing from the outside a bunch isn't looked upon favorably.

 

[The Panther]

So what's the story behind OT shooting percentage being so much higher this season, suddenly?

 

[Doctor No]

One thing that I should have corrected for but I wasn't sure if it would materially impact the results - there's a bit of an apples-oranges thing going on because I included all shot/save data for all periods. Therefore, the first three periods' data include mismatched teams but the overtime data only includes closely-matched teams (since the game went to overtime).

Here's the same data but only including games that went to overtime.

Overall by period:

Regular Season	Period 1	Period 2	Period 3	Period 4	Total
201617​	0.937	0.921	0.925	0.843	0.922
201718​	0.926	0.922	0.916	0.850	0.917
201819​	0.921	0.916	0.915	0.829	0.912
201920​	0.918	0.915	0.916	0.844	0.911
202021​	0.920	0.912	0.912	0.830	0.909
202122​	0.928	0.911	0.909	0.843	0.911
202223​	0.911	0.913	0.913	0.832	0.907
202324​	0.922	0.907	0.908	0.815	0.906
202425​	0.917	0.906	0.906	0.754	0.901

Relative to total save percentage, by period:

Regular Season	Period 1	Period 2	Period 3	Period 4	Total
201617​	101.6%​	99.9%​	100.4%​	91.4%​	100.0%​
201718​	101.0%​	100.5%​	100.0%​	92.7%​	100.0%​
201819​	101.0%​	100.4%​	100.3%​	90.8%​	100.0%​
201920​	100.7%​	100.4%​	100.4%​	92.5%​	100.0%​
202021​	101.2%​	100.3%​	100.3%​	91.3%​	100.0%​
202122​	101.9%​	100.0%​	99.7%​	92.5%​	100.0%​
202223​	100.4%​	100.6%​	100.6%​	91.7%​	100.0%​
202324​	101.7%​	100.1%​	100.2%​	89.9%​	100.0%​
202425​	101.8%​	100.6%​	100.6%​	83.7%​	100.0%​

As far as why this year's is lower, i haven't checked (but can) but I bet it's because early in the season teams care less about playing carefully in overtime. Later in the season where teams are more carefully watching the standings, I bet things tighten up a bit more.

 

[wetcoast]

The save percentage drop is expected because there are more dangerous shots in OT. It'd be interesting to compare XG saved, too.

Someone is going to come out with McDavid/Draisatl scoring rates per 60 mins in OT one of these days I fear.

 

[Reverend Mayhem]

The goalie rule changes were also gradual, not all at one off season.
Plus I said that was just one of the reasons.

Yeah, like the reason the product has been so good lately is the growth the NHL made was sustainable. The changes were done incrementally enough to make the game look functionally the same. But that was all done on purpose. They talked endlessly about growing the game and they made their target. The youth coaching ranks got a great infusion of talent the last 10-15 years as well.

These kids are fantastic athletes. I just worry they may have spent too much time on the ice rather than in the room, but that's how you make a great hockey talent. Not necessarily a great hockey player, though.

 

[Elitersson]

Save percentage by regular season period, 2016-17 to present. Any errors in the results are from errors in my underlying data.

Regular Season	Period 1	Period 2	Period 3	Period 4	Total
201617​	0.921	0.909	0.914	0.843	0.913
201718​	0.918	0.907	0.915	0.850	0.912
201819​	0.914	0.906	0.913	0.829	0.910
201920​	0.914	0.906	0.912	0.844	0.910
202021​	0.914	0.906	0.908	0.830	0.908
202122​	0.914	0.902	0.909	0.843	0.907
202223​	0.911	0.898	0.906	0.832	0.904
202324​	0.908	0.899	0.906	0.815	0.903
202425​	0.906	0.898	0.902	0.754	0.900

Save percentage by regular season period (relative to the overall save percentage for the season):

Regular Season	Period 1	Period 2	Period 3	Period 4	Total
201617​	100.8%​	99.5%​	100.0%​	92.3%​	100.0%​
201718​	100.7%​	99.4%​	100.3%​	93.2%​	100.0%​
201819​	100.5%​	99.6%​	100.3%​	91.1%​	100.0%​
201920​	100.5%​	99.6%​	100.2%​	92.7%​	100.0%​
202021​	100.6%​	99.7%​	100.0%​	91.4%​	100.0%​
202122​	100.8%​	99.4%​	100.2%​	93.0%​	100.0%​
202223​	100.8%​	99.4%​	100.3%​	92.1%​	100.0%​
202324​	100.5%​	99.5%​	100.3%​	90.2%​	100.0%​
202425​	100.6%​	99.8%​	100.2%​	83.7%​	100.0%​

Interesting to me that save percentage in the 2nd period is consistently a decent bit lower than the 1st and 3rd periods.

 

[Doctor No]

Interesting to me that save percentage in the 2nd period is consistently a decent bit lower than the 1st and 3rd periods.

Good point - this pattern persists pretty much as far back as I have data.

My belief is that average shot difficulty increases when plays are less structured (consider breakaways and odd-man rushes), and that the propensity for less structure increases with the long change.