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PDO and Luck: Projecting Progression / Regression in the NHL

May 22, 2012, 3:03 PM ET [12 Comments]
Travis Yost
Ottawa Senators Blogger • RSSArchiveCONTACT
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Perhaps one of the toughest -- and longest-running -- annual debates is trying to forecast whether or not a pending unrestricted/restricted free agent is worth the money being spent based on a set market value.

Some names -- P.A. Parenteau and Jason Garrison immediately come to mind -- have enjoyed incredibly successful point-driven seasons and are expecting lucrative contracts.

On the other end of that spectrum, players like Alex Semin have watched as their market value has fallen off the proverbial cliff. There's little denying Semin's overall skill set, but legitimate questions arise concerning his mentality and approach towards the game. Just how engaged is he right now? And, is his alarming drop-off in point production the direct result of depreciating skills, lack of effort, or a combination of factors?

Of course, the ultimate variable in all of this is luck. Whether or not the coaches and media will admit it, hockey is an incredibly luck-driven game. Simulate a season -- all variables held -- a thousand times, and you may end up with the same number of varying outcomes.

The problem with the luck factor is that it's difficult -- if not impossible -- to quantify. Collectively, luck is a non-factor; for each lucky play(or, player), the alternative -- an unlucky play(or player). When you get to individual player analysis, though, things get a bit tricky. Like it or not, some players will continually hold above the league mean; others will rarely benefit from the generous bounce.

The general idea, though, is that the majority of league talent will float around some kind of average. Finding the disparity between a player's output and the league average concerning luck, though, is another difficult task.

Enter PDO -- the one statistic that may help quantify the level of luck(or lack thereof) a player's receiving over the course of a lengthy sample size. Even though it's treated as an advanced statistic, the measurement is actually quite simple: Shooting percentage plus save percentage, with the league mean set at 1000. Players above the 1000 mark can expect to regress there in the future; players below the 1000 mark can expect to progress there in the future.

The statistic operates on three principles.

(a) Shooting percentage is primarily luck-driven;
We've gone through this a billion times - a season's worth of shots, whether for a team, while a player's on the ice, or just those taken by an individual player, simply isn't a large enough sample to overcome the role of luck in putting pucks in the net.

(b) Save percentage is primarily luck-driven;
The spread of goaltending talent is much smaller than most people suspect, and 29-year-old goalies jumping from obscurity to the All-Star game are hardly uncommon. Again, we've got single-season sample size issues, backup goalies, and a whole lot of luck.

(c) Apparent talent there is in these quantities, particularly offensive finishing ability, shows up as negative talent at the other end of the ice
The apparent talent there is in these quantities, particularly offensive finishing ability, shows up as negative talent at the other end of the ice.

Add #1 and #2, and you get a statistic that is almost 100% luck. How can this be? Surely there are players or lines who are higher-percentage finishers than others and can also play adequate defense? I'm not saying there aren't but for the vast majority of NHL regulars, a high PDO in one season comes crashing down the next. And many players with high one-ice shooting percentages get them by cheating offensively, which leaves them susceptible to higher-percentage opportunities against them at the other end of the ice.


Logically, it does make sense.

It should be noted that PDO -- most like any statistical measurement, regular, advanced, or otherwise -- isn't a be-all, end-all for player analysis. It's simply one way of trying to quantify player luck.

So, how did the 2011-2012 Ottawa Senators look here? Take a look below, courtesy BehindTheNet.



A few notes:

-- Yesterday, I pointed out via Twitter that Filip Kuba's on-ice save percentage from 2010-2011 to 2011-2012 absolutely skyrocketed, which certainly helped his +/- rating, and subsequently assisted in the eradication of his reputation that the thirty-five year old was a complete and utter pylon one year ago. Pretty much every player on the team -- with the exception of Nick Foligno, naturally -- saw their on-ice save percentage improve from last year to this year with the addition of Craig Anderson full-time, but Kuba's move from .883(team worst) to .923 at even-strength was enormous.

-- Why am I leading off with on-ice save percentage? Well, along with PDO, it's assisting in evaluating Kuba's true season in 2011-2012. There's no denying how much an improvement in goaltending assisted Kuba, but what about the absurd TOI he logged with Erik Karlsson, one of the most dynamic D in the National Hockey League? And, taking a look at PDO, Kuba was the team's luckiest player -- shot percentages were high for, shot percentages were low against, and a few pucks probably bounced in his favor. In fact, Kuba individually posted his third-best shooting percentage of his career at 7.7% -- his best since the fluke fifteen-goal season of '06'-07(14.2%).

-- The one argument you can make in favor of Filip Kuba? A return to health really aided his game. That's certainly legitimate, but with so many other variables working against him, is it possible he was just more lucky(and more protected) than anything else?

-- Let's get off Filip Kuba for a minute and touch on the most terrifying element of this list: Bobby Butler as the team's second luckiest player. The consensus among the Ottawa Senators fan base this year was that Bobby Butler was probably the biggest disappointment, player development or otherwise, on the big-league roster this season. Is it alarming that he managed to accomplish that in a season where his bacon was probably saved more than once?

-- Nice to see Erik Karlsson just slightly above the mean. Hard to believe a seventy-eight point player didn't benefit a whole lot from the luck factor, but when you consider the other variables, it's not eyebrow-raising. Karlsson held the exact same shot percentage for the second year in a row, and his .917 on-ice save percentage at even strength was just .012 better than last year's on-ice save percentage with the Elliott/Leclaire debacle. This speaks to Gabriel Desjardins' third element: Offensive-minded players that tend to take risks/chances will watch their PDO balance with a higher number of scoring opportunities against.

-- Of returning players, only Chris Neil was a bit unlucky during the regular season. For many, Chris Neil made his mark on the playoffs, playing some of his best hockey late against the rough-and-tough New York Rangers. You probably won't be surprised, then, when I inform you that through the admittedly small sample size, Chris Neil was the team's luckiest player after Jim O'Brien, posting a 1053 against New York. Funny how these things work out sometimes. [For those curious, Jared Cowen had the unluckiest run of qualified players, posting a 913].

-- Outside of the Ottawa Senators, some of your luckier players include a pair of talents from the Boston Bruins in Rich Peverley and Chris Kelly(1056), followed by another former Ottawa Senator in Mike Fisher(1045). Of the notable point and goal-scorers, it shouldn't really surprise that Radim Vrbata(1038), Ray Whitney(1037), and Valtteri Filppula(1035) rounded out the top-ten. Solid players, but I think you can find a consensus on HockeyBuzz and other hockey-based web sites that these names probably won't fill your league's highest scorers list with regularity.

-- As for your league's unluckiest players: Nino Niederreiter was the only sub-900 man at 898, and again, I largely agree. While Niederreiter was a complete enigma and frustrated his coaching staff in a tough rookie year, it's almost unfathomable to find a player skating 10:07 per for 55 GP tally just one(!) point in total. In fact, since BTN has been keeping track, El Nino's 898 PDO is the lowest recorded. Eric Boulton(PDO 931) was another name clocking in at third, as he managed to score zero --literally, zero -- points through fifty-one games played. Cam Fowler's eleven-point regression may have had some to do with the Anaheim Ducks collectively regressing from last year, but a notable PDO drop from to 976 to 962(18th overall) didn't help, either. Worth looking at: Fowler's on-ice save percentage moved wildly in his favor from one year ago, running from .888 to .917. Is Fowler curtailing scoring opportunities for stronger defense? Or, is the return of Jonas Hiller to health that big?

Just something to chew on heading into the off-season. Have any questions - get 'em off in the comments section.

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Thanks for reading!
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