NHL Playoffs Statistical Preview

The stats love the Kings.

The stats love the Kings.

(Note: From time to time, I’ll take a break from proposing new sports ideas. This is one of those times.)

While the hockey stats revolution is still about a decade or so behind baseball, there are still some pretty telling stats in our toolbox today. My favorites are Corsi, Fenwick, and PDO.

Here’s a description of each from the awesome Stats.HockeyAnalysis.com:

  • Fenwick = Shots + Missed Shots
  • FF% = Fenwick For% = Fenwick For / (Fenwick For + Fenwick Against)
  • Corsi = Shot Attempts = Shots + Missed Shots + Blocked Shots
  • CF% = Corsi For% = Corsi For / (Corsi For + Corsi Against)
  • PDO = Shooting Percentage + Save Percentage while on the ice

There’s obviously a lot of overlap, but we’ll just ignore that for now. The main takeaway is that possession and shots are extremely important.

I compiled the FF%, CF%, and PDO on all 30 NHL teams from the 2013-14 regular season and standardized them into a z-score. For Fenwick and Corsi, a higher z-score is good. For PDO, a lower z-score is good.

I averaged these figures up in the “Total” column ((FF + CF – PDO) /3) and sorted them by that metric. To compared them to the actual regular season results, I also added the regular season standings points and goal differential.

Team FF% FFZ CF% CFZ PDO PDOZ Total Points Goal Dif
Los Angeles 56.1 1.83 56.8 2.01 1000 0.00 1.28 100 32
New Jersey 53.6 1.07 54.4 1.29 985 -1.33 1.23 88 -11
Chicago 55.4 1.62 55.5 1.62 999 -0.09 1.11 107 47
San Jose 54.6 1.38 53.7 1.09 998 -0.18 0.88 111 49
Florida 50.8 0.23 51 0.28 980 -1.77 0.76 66 -72
NY Rangers 52.6 0.77 52.4 0.70 997 -0.27 0.58 96 25
St. Louis 53.7 1.10 53.1 0.91 1007 0.62 0.46 111 57
Vancouver 51.6 0.47 51.3 0.37 995 -0.44 0.43 83 -27
Ottawa 51 0.29 52.4 0.70 997 -0.27 0.42 88 -29
NY Islanders 49.1 -0.28 49.4 -0.19 984 -1.42 0.32 79 -42
Detroit 51.5 0.44 51.5 0.43 1000 0.00 0.29 93 -8
Winnipeg 50.5 0.14 50.1 0.02 994 -0.53 0.23 84 -10
Carolina 49.6 -0.13 50.3 0.08 994 -0.53 0.16 83 -23
Nashville 49.4 -0.19 48.5 -0.46 989 -0.97 0.11 88 -26
Dallas 50.9 0.26 50.5 0.14 1002 0.18 0.07 91 7
Tampa Bay 51.3 0.38 51 0.28 1007 0.62 0.02 101 25
Boston 53.4 1.01 53.9 1.15 1025 2.21 -0.02 117 84
Phoenix 50 -0.01 50.5 0.14 1003 0.27 -0.05 89 -15
Philadelphia 49.2 -0.25 50 -0.01 1003 0.27 -0.18 94 1
Pittsburgh 49.2 -0.25 48.7 -0.40 1001 0.09 -0.24 109 42
Calgary 47.7 -0.70 46.3 -1.11 988 -1.06 -0.25 77 -32
Columbus 49.8 -0.07 49.9 -0.04 1008 0.71 -0.27 93 15
Minnesota 48.8 -0.37 48.6 -0.43 1010 0.89 -0.56 98 1
Washington 47.1 -0.88 47.7 -0.69 1002 0.18 -0.58 90 -5
Montreal 47.9 -0.64 46.7 -0.99 1005 0.44 -0.69 100 11
Anaheim 50.1 0.02 49.8 -0.07 1024 2.13 -0.72 116 57
Edmonton 44.1 -1.78 44.3 -1.70 990 -0.89 -0.87 67 -67
Buffalo 42.8 -2.17 43 -2.09 982 -1.59 -0.89 52 -91
Colorado 46.7 -1.00 47 -0.90 1018 1.59 -1.17 112 30
Toronto 42.3 -2.32 42.9 -2.12 1013 1.15 -1.86 84 -25

 
It’s not hard to see why Toronto and their notoriously anti-analytics front office fell off the rails, but how did Colorado manage to achieve a No. 1 seed in the West? (Answer: Unsustainably over-achieving goaltending from Semyon Varlamov.)

For the sake of comparing these stats to regular season results, here’s how Total looks plotted against goal differential:

playoff data 2

(Sorry some of those are cut off. The far left is Toronto, and the far right are Los Angeles and New Jersey.)

The correlation is only .1845, which suggests that these metrics should probably only be used as a guideline in telling us what teams may have over- and under-achieved this season relative to their actual performance.

First round match-ups

Ok, so how do these teams’ stats compare for the first round match-ups?

Home Ice Total Road Ice Total Difference
Colorado -1.171 Minnesota -0.512 -0.66
St. Louis 0.106 Chicago 0.905 -0.80
Anaheim -0.575 Dallas 0.289 -0.86
San Jose 0.926 Los Angeles 1.233 -0.31
Boston 0.101 Detroit 0.356 -0.25
Tampa Bay 0.018 Montreal -0.377 0.40
Pittsburgh -0.200 Columbus -0.483 0.28
NY Rangers 0.753 Philadelphia -0.244 1.00

 
In the West, every matchup’s lower seed has a higher total, which suggests that upsets could be rampant. Most notably, Minnesota and Dallas have a considerable edge over the two No. 1 seeds. And whoever emerges from the San Jose vs. Los Angeles showdown (two of the three highest Totals in the playoffs) should be a serious contender to make the Stanley Cup Finals.

In the East, it’s a bit more chalk, but again, a No. 1 seed (Boston) has a lower total than its opponent (Detroit).

Does this mean all the No. 1 seeds are going down? No, probably not. But it does indicate they’re very susceptible to being upset—not just in the first round, but in every round of the playoffs.

Vegas odds

Finally, let’s take a look at how these Total figures for each team compare to Vegas. My (extremely unscientific and non-statistically sound) formula for a stat I call “BetFigure” is:

BetFigure = [(Total Differential + 2.5) * 0.2] / Vegas Win Percentage

From my (again, unscientific) experience, anything over 1.50 is generally a profitable bet.

Team Line Win Pct Total Opponent Total Total Diff BetFigure
Detroit 235 29.9% 0.356 Boston 0.101 0.25 1.85
Dallas 165 37.7% 0.289 Anaheim -0.575 0.86 1.78
Columbus 210 32.3% -0.483 Pittsburgh -0.200 -0.28 1.37
Minnesota 115 46.5% -0.512 Colorado -1.171 0.66 1.36
Chicago -105 51.2% 0.905 St. Louis 0.106 0.80 1.29
Los Angeles 125 44.4% 1.233 San Jose 0.926 0.31 1.26
NY Rangers -150 60.0% 0.753 Philadelphia -0.244 1.00 1.17
Tampa Bay -117 53.9% 0.018 Montreal -0.377 0.40 1.07
Montreal -103 50.7% -0.377 Tampa Bay 0.018 -0.40 0.83
Pittsburgh -250 71.4% -0.200 Columbus -0.483 0.28 0.78
San Jose -145 59.2% 0.926 Los Angeles 1.233 -0.31 0.74
Philadelphia 130 43.5% -0.244 NY Rangers 0.753 -1.00 0.69
Colorado -135 57.4% -1.171 Minnesota -0.512 -0.66 0.64
St. Louis -115 53.5% 0.106 Chicago 0.905 -0.80 0.64
Boston -280 73.7% 0.101 Detroit 0.356 -0.25 0.61
Anaheim -190 65.5% -0.575 Dallas 0.289 -0.86 0.50

 
So there you have it, Detroit and Dallas. Take it to the bank. Guaranteed*

*Maybe

 

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Restructuring the March Madness bracket

NewBracket1
Realistic rating: 5.5

With a No. 7 and No. 8 seed qualifying for the Final Four, this year’s tourney again highlights some of the same issues that have always plagued college basketball—the extreme unpredictability of the postseason. While most fans probably love this aspect of the sport, it brings up a number of problems with the college basketball season as a whole, namely: the meaningfulness of the regular season and the frequency with which the best team actually wins the championship.

Perhaps the most fundamental concept every sport must confront is how to balance fairness vs. excitement—or in other words, how often should the best team win? There are some sports that probably have too high a percentage (e.g. sprinting, NBA) at the expense of excitement/unpredictability, while others have far too low a frequency of the best winning but enjoy a very high level of excitement/unpredictability (e.g. MLB).

College basketball falls about as far on the excitement end of the spectrum as any sport. This makes the postseason extremely fun and unpredictable, but the regular season, well, is just about meaningless. Plus, the “champion” is rarely the best team.

This is due to the postseason’s structure—a 68-team single elimination tournament in which every team, with the exception of the eight involved in play-in games (no, I’m not calling those “round one”), has ostensibly the exact same starting position, requiring the six victories to win the championship (i.e. there’s not much reward for regular season performance other than a higher seed, which in many cases is actually a negative.) Thus, as much as ESPN likes to hype a regular season game such as No. 1 Syracuse vs. No. 5 Duke last month, it really doesn’t matter who wins, as there’s not much reward for the victor.

A couple of weeks ago on Deadspin, I wrote a piece discussing some of these issues with this format and proposed a few alternatives, such as a World Cup style, a bye tiered bracket, and a standard bracket with randomized lower seeds. (The heavy math for these proposals is there.) While these were all certainly improvements on the current format, they were, as Mike Ehrmantraut would say, a “half measure.”

Expanding (Yes, Expanding) the Bracket

Considering there are 351 Division I basketball teams, allowing 68 (19.4%) into the postseason a good figure if you must have a single-elimination, limited-tier (by “tier” I mean giving certain teams byes or other hard advantages other than playing a weaker first round opponent). However, contrary to what most hardcore fans may believe, making the postseason more exclusive will only make the regular season more meaningful for roughly the top 25% of teams. With fewer teams in the tourney, the regular season would be far less meaningful for the bottom 75%, because for the vast majority of teams in smaller conferences, their season is entirely meaningless only a dozen games into the season. (Note: Yes, there are incredibly dumb conference tournaments that render single-bid conference regular seasons meaningless, but we’ll just ignore that for now.)

But how can you make the regular season more meaningful for all 351 teams without making the postseason even more of a crapshoot? Here are a couple of straightforward solutions, which could really be applied to all sports:

1. Simply have best-of-three series at certain rounds of the tourney. This would be highly impractical for a number of obvious reasons, though, so let’s assume we have to stick to single elimination. Also, while decreasing the randomness, best-of-three series still wouldn’t make regular season success more meaningful.

2. Have a dramatically bye-tiered bracket. The example for this kind of setup in the Deadspin piece only had three bye tiers: #1-4 seeds on bye to the round of 32, #5-8 at the normal starting position, and #9-16 with a play-in game to the first round. This still didn’t result in quite as much significance for regular season success as I would have liked, though, but how about some of these?

NewBracket1

Or

NewBracket2

In each of these brackets, there’s now a much greater reward for landing a higher seed, which would make the regular season far much more meaningful while also giving much higher likelihood to the chances of the best teams being there the final weekend. I’m a huge proponent of tiered bracket systems in which higher seeds get greater rewards (in the form of byes or otherwise) and wish more leagues other than the NFL would adopt such measures. (More on this in future posts to be sure.)

I’m not sure if I’ll be rooting for UConn or Kentucky this weekend. Should either win, it will be a glaring mark on the legitimacy of the NCAA champion title, but at the same time, it might garner further exposure for the sham the current format really is.

Bottom line: These proposals really don’t shake up things all that much (i.e. still single-elimination bracket, still four regions, etc.), but with the NCAA making a boatload of money as is, the probably won’t want to change much. Still, with even the highest regular season game (a 5000+ game sample size) rating falling well below almost all of the 68 tournament games, there’s certainly a missed revenue stream opportunity.