Yes, The Penguins are Getting Lucky

Hey there, long time no talk.

Let’s air this out right now: the Pittsburgh Penguins are getting lucky. Very, very lucky. Like totally, unbelievably, unsustainably lucky.

The Washington Capitals have out-attempted, out-chanced, and generally pushed the Penguins around in this series. The Columbus Blue Jackets kind of did the same thing. But guess what: it’s nothing we haven’t seen before.

Problem: An Over-Reliance on PDO

PDO Explained

Let me walk you through a little thing called PDO. PDO is a rough measure of how a team or player compares to the league average in on-ice shooting percentage and on-ice save percentage (looking at an overall team’s PDO can be simplified to simply “the team’s shooting and save percentages”). Given that we are focusing simply on shots on goal (as opposed to shot attempts), we can view shooting percentage and save percentage as two parts of a continuum--a shot on goal is either a goal or it is a save. Given that we have a completely binary relationship between goals and saves, we can make the assumption that on the whole, teams in the NHL should have a PDO around 100.

On the average, the assumption in the stats community is that teams will shoot around 8.5% over the course of a season. It’s a pretty reliable aggregate that includes both high scoring forwards (like Sidney Crosby, who managed 43 goals on 255 shots--good for a 17.3 S%), as well as very low-scoring defensemen (like Brian Dumoulin, who managed just 1 goal on 78 shots this year--a 1.3% conversion rate). This is a trend that is also influenced by special teams: players who get more power play time tend to have slightly inflated shooting percentages compared to players who don’t get power play time.

On the other side of the continuum, we expect goalies to save about 91.5% of the pucks they see. Again, this aggregates all different scenarios: starters might hover closer to 92% while backups often finish the season closer to 90%. Similarly, goalies tend to save a much higher percentage of 5-on-5 shots (somewhere north of 93% based on some quick, back of the napkin calculations), while very good goalies will struggle to stay above 90% while their team is killing a penalty.

While we expect the majority of teams will hover around a year-long PDO of 100, there are certainly exceptions. In most instances we can break the teams  that have a higher PDO into one of three categories: Stanley Cup Favorites/Vezina Caliber Goalies/Both. Want an example? Here are the teams that finished with the highest PDO this year:

  1. Washington Capitals | 102.90 | [Both, and Braden Holtby is the current reigning Vezina winner]

  2. Minnesota Wild | 101.76 | [Both, although Devan Dubnyk was robbed of a nomination]

  3. Chicago Blackhawks | 101.44 | [Stanley Cup Favorites, and the closest we’ll likely get a dynasty in the “parity era”]

  4. Columbus Blue Jackets | 101.43 | [Vezina Caliber Goalie, and let’s be real Sergei Bobrovsky is going to win this year, for the second time in his career]

  5. Pittsburgh Penguins | 101.27 | [Stanley Cup Favorites, and you may have heard, reigning Stanley Cup champions]

While there is a decent amount of positive correlation between carrying a high PDO and being considered a “good” team, teams are not typically immune to the principle of regression. Regression suggests that over time, teams will always move towards the average, or in other words, “hot teams will go cold” and “cold teams will get hot”. We have already seen this phenomenon verified with 3 of the teams listed above (the Blackhawks and Wild could not buy a goal in their opening playoff series, while the Blues Jackets couldn’t get a save from their goalie). The phenomenon seems to be repeating again with the Capitals as both their shooting and save percentage have nose-dived since the playoffs started. And trust me, regression is coming for the Penguins, too. The question, then, is when?

PDO Examined

Before we go any further, let me get this out of the way now: through 7 playoff games, the Penguins boast a 13.8% SH% and and a 93.6% SV%, that’s equivalent to a 107.4 PDO. It’s unbelievable, and it WILL NOT LAST for the remainder of the Stanley Cup playoffs.

But, looking at other successful teams this season, it’s not entirely impossible that what the Penguins are doing currently can last for a few more games. Take for example the Washington Capitals, who, during an 11-game stretch from January 5 - January 24 never dipped below a single game PDO of 107.84. For that nearly three week stretch the team had a PDO of 112.71.

Similarly, when we compare rollings averages for all of the five teams discussed above, we see extremely large, long swings (of 25 games) where the Capitals held an average in excess of 108, the Wild topped 105, and the Blue Jackets topped 104. By contrast, the Penguins are currently on their “luckiest” streak of the season (looking again at 25 game rolling averages), combining the playoffs so far, plus roughly the last quarter of the regular season, and the team is still only peaking at a 102.84.

Yes, that is lucky, and please don’t misunderstand me: if you’ve watched the way the Penguins have been smashed to bits in pretty much every game they’ve played this postseason, I’m not saying it’s positive. But here’s the thing: operating as though the regular season has no bearing on the Penguins’ current play is to ignore a ton of big, usable data points.

Saying that a team is currently on a lucky streak without also acknowledging that all teams have lucky streaks (and unlucky streaks) is not a particularly prudent way to say that you’re mad that the Penguins are blowing up your bracket.

Hope: Just Beat Washington

The Penguins have to figure out a way to sustain more territorial advantage, they need more time in the offensive zone, and they need to try to tighten up the shots/shot attempts against Marc-Andre Fleury. They have to because it’s been a really, really long time since a team has successfully scored its way to the Stanley Cup. They have to because they aren’t going to score at 14% for another 10 games.


They can also regress to the mean and still beat pretty much any team, except for Washington. After watching the first two games of this series, I feel confident in saying that the Capitals are the best team remaining in the postseason. They’ve been unlucky against the Penguins, but they have not been bad. The Penguins will likely need to squeeze out a little more luck, and then trust that they can return to a possessive, suppressive force like we saw at this time last year. If they do, it could be a very pleasant spring in Pittsburgh.

Welcome (Back)

Hi there, I’ve been gone a long time. My name is Andrew Roman and I’m really captivated by hockey, the Pittsburgh Penguins, stats, and the science behind the great game. If you know me, or by some odd chance recognize my name from previous websites, you know these things are not new. In fact, writing about the Penguins and the NHL at large had reached such a point of oldness that I really needed a break.

Some of the reasons for taking a break are really good--I do work that I enjoy, and that I get paid good money for, which is great, but those things also makes it difficult to write on a daily basis. But some of it is not so good--at the end of the Dan Bylsma/Ray Shero era, and during Mike Johnston’s time as head coach it became difficult to say new things about a coach, a team, a system that had grown stale.

But now things are a little bit different. And, honestly, the fact that the Stanley Cup is back in Pittsburgh is only a very small reason why I’ve pulled myself out of the Blogger’s Retirement Community Home. You see: the Penguins won the Cup with a singular focus on maximizing team strengths. While that may not seem that unique or different, there is a standard, default motivation in most people that too much of a good thing can turn into a bad thing. This line of thinking--which is, in a very literal sense, a self-preservation instinct--seems to be particularly prominent in the General Managers and Head Coaches of professional sports teams of all sorts (and that’s to say nothing of how ingrained that point of view is in an “old-school” sport like hockey, where player assessments and coaching strategies have hardly evolved from the standards of the 1970s).

That makes it all the more exceptional that a GM nearing 70 years old and a coach who had been fired four times in the last 10 years would be willing to step out of their way to do something we hardly see: cast aside the kind of “equilibrium” typical of hockey teams (which could be considered a synonym for “boring”) and build a team that essentially displaces any fear of weakness with a belief that the team’s native strengths are so much greater than any other opponent’s that the weaknesses don’t matter.

This notion, that the 2015-16 Penguins did something unique, cuts to the core of what I want this site to be about. I want this to be a site based more on questions than answers; particularly questions like “Why do they do that?” and “Why doesn’t everyone do that?” These questions are derived from a book entitled The Numbers Game: Why Everything You Know About Soccer is Wrong written by Chris Anderson and David Sally (seriously get it, it is amazing, even if you don't like soccer). For fear of diverting too far, I have been greatly influenced by their perspective, one that I do fear has been forgotten by far too many in hockey’s “analytics” community. Anderson and Sally continually remind their reader that in order to be an analyst, one of the greatest challenges you will be faced with is to constantly ask yourself: “How might I, and my numbers, be incorrect?”

I don’t say that to poo-poo the analytics community to which I only wish I could belong. I say it because hockey has finally reached the point where we know how to collect data, and we have reason to believe that the data we collect matters for something. But with that in mind, now is the time for even greater caution. Bearing with that, I want this site to be accessible to individuals regardless of their exposure or knowledge of social scientific research, statistics, and advanced hockey stats. By necessity, it also must be a place where I acknowledge the strengths and weaknesses of the articles (both research and casual in nature) that I produce, and I ask that you, whoever may read this, come to this site with an inquisitive nature, and be willing to ask the questions that may spin off of the content provided.

With all of that important sounding stuff out of the way, here’s what you need to know: I want to be upfront and say that Reggie’s House isn’t going to be a place for up-to-the-minute updates about the Penguins. Yes, I’m going to cover significant roster moves, trades, injuries, and the like, but only the really big stuff. At least as of site launch, my expectation is to more or less alternate between “big” research/analytic-type articles and localized Penguins stories. Depending on certain factors, that balance could change, but more than likely it would change in the direction of doing more research and less opining, because trust me, you do not need me to tell you how to feel about the Penguins.

In addition to the written content, I am very pleased to announce the creation of the Reggie’s House Podcast. I’ll be joined by Mike Swanson for a weekly(?) dive into the Penguins and the league at large. This new medium should fill you up with all of the Pens-centric, light-hearted takery you can ask for. I promise it will be fun.

The first episode of the podcast should be out sometime on Monday, October 3, and the first article (examining "weak" and "strong" links in a team's lineup) should hit sometime later this week.

So welcome, let’s learn together.

LGP,

Andrew