Moved

Wednesday, November 29, 2006

Is There Hope for the Flyers?

Now that the Philadelphia Flyers have moved beyond the Bobby Clarke/Ken Hitchcock era, I thought I'd take a detailed look at their performance to see what stylistic changes in their play have accompanied their improved record as of late (they were 1-6-1 before Regime Change, and are 6-8-2 afterwards).

The most basic indicator of performance is the Goals For/Against ratio, which is our strongest guide to determining win/loss results for a team. The improvement there has been dramatic:

	Goals For/Game	Goals Against/Game	Goal Ratio
Before	1.875	4.125	0.455
First 8 After	2.25	4.00	0.563
Last 8	2.75	1.75	1.571

It would appear that they floundered early on, continued their poor play in the wake of the shakeup, but then have actually turned things around in the last 8 games. Granted, 8 game snapshots aren't much of a statistical sample, but if they made enough sense for Flyers management to flush a front office down the drain, it's good enough for blogwork.

The wierd part here is that the Goal Ratio is improving, while the Shooting Ratio (Shots For/Shots Against) has taken a dive. The goaltending is hot in Philly these days, with Antero Niittymaki taking the lead job away from the injured Robert Esche. Save percentage was .862 under Hitchcock, .856 in the first 8 games after his departure, and .949 over the last 8 games. Clearly the current pace is unsustainable, but anything around the .900 mark would give the Flyers a fighting chance. As for the shooters, the improvement has been equally dramatic. Shooting percentage was only 5.8% early on, 6.6% in the second 8 games of the season, and 11.7% over the last 8. Considering that league-wide shooting percentages tend to be around 9-10%, if the shooting percentage comes back down a bit but the number of shots returns a more normal level, the overall offense should remain about the same - mediocre.

	Shots For/Game	Shots Against/Game	Shot Ratio
Before	32.25	29	1.11
First 8 After	33.9	27.9	1.22
Last 8	23.5	34	0.69

Another noteworthy aspect is that Shot Quality wasn't a factor in their early performance. I like to make fun of Derian Hatcher's glacial speed as much as the next guy, but using my (relatively crude) measure of Shot Quality, an average shot had a 9.88% chance of going in last season. Philadelphia's opponents took shots that would be expected to score anywhere from 9.5% to 9.8% of the time, using the three 8-game periods we're discussing here. On the offensive end, Flyer shooters took above-average shots. Before the front office change, 10.1% of shots would be expected to score, and in the immediate aftermath, that measure rose to 10.7%. In their latest 8-game stretch, they've reverted closer to the norm at 9.95%. So what does all this mean? Basically, the Flyers gave up a normal amount of relatively average shots, yet their save percentage wallowed in the mid-.800's through the first 16 games. Clearly, goaltending was to blame more than a lumbering defense. On the opposite end, they also ran into some hot goaltending (Philly's actual shooting percentage was much lower than Shot Quality would have indicated).

As far as Hits go, we don't see a huge shift in either direction, just an overall reduction of about 10% in hitting by both the Flyers and their opponents:

	Hits For/Game	Hits Against/Game	Hits Ratio
Before	15.4	19.6	0.78
First 8 After	15.5	14.4	1.08
Last 8	14.5	16.3	0.89

Looking at Takeaways, there has been clear improvement in this area - the Flyers now swipe the puck away more often than their opponents, rather than getting it stolen away constantly:

	Takeaways For/Game	Takeaways Against/Game	Takeaway Ratio
Before	5.13	7.75	0.66
First 8 After	4.88	6.88	0.71
Last 8	7.25	6.88	1.05

As for Giveaways, there isn't any strong trend here, and as discussed previously, Giveaways haven't been shown to have a strong correlation with performance. It may well be that a team with a large number of Giveaways just has the puck more often, and thus more opportunities to cough it up:

	Giveaways For/Game	Giveaways Against/Game	Giveaway Ratio
Before	10.63	9.75	1.09
First 8 After	16.5	9.75	1.69
Last 8	12.38	10.63	1.16

Team commitment to defense appears to be rising - Blocked Shots per Game went from 11.63 before Hitchcock walked the plank, 13.38 in the first 8 games after, and 14.9 over the last 8. If the Flyers continue this focus on their own end, and Niittymaki manages to post a save percentage anywhere north of .900, the team has a shot at getting back into the playoff picture. Perhaps they don't need to hit the panic button and trade Peter Forsberg away after all...

Monday, November 27, 2006

It's The All-Request Hour...

Rich over at American Hockey Fan asked today for an in-depth comparison between past and present Bruins centermen Joe Thornton and Marc Savard, so here we go. This is pretty much an ad-hoc analysis (rushed to the finish so I can get to a meeting), but if you feel something is missing, feel free to chime in...

OFFENSE:
As of today (11/27/2006), Thornton and Savard each have 27 points, the difference being Big Joe's 7 goals to Savard's 6, and Savard having played 3 less games (which gets Savard into 7th spot over at Hockey Recap for points per minute). Time on the ice per game is nearly identical, (19:16 vs. 19:17), so it's not like one guy is getting more opportunity than the other, and each has 2 power play goals, so it would appear at least that neither is getting a big advantage in that area. One interesting difference is that Savard tends to take more shots than Thornton (68-50), albeit with a lower shooting percentage (8.8 vs. 14.0) This is true even if you look at career stats, where Savard averages about 2.3 shots per game and sports an 11.3% shooting percentage, to Thornton's 2.1 shots per game and 15.1% shooting percentage. Note that Savard is on pace for a personal high in Shots this year (~275), so if his shooting percentage gets back close to his career mark of 11.3%, he could achieve his first 30-goal season. What I really need to work on is a quick way to do Shot Quality analysis on a player-by-player basis, to see where the difference in shooting percentage comes between these two players. I'll save that for another day...

As far as assists go this season, I show 13 of Thornton's 20 assists being "first assists", along with 13 of Savard's 21. Last year, Thornton and Savard ranked among the league leaders in overall assists, but the difference was that over 72% of Thornton's were first-assists, compared to 58% of Savard's. One could make the argument that first-assists are a better indicator of offensive impact than the overall number. It looks like a wash so far on this count.

DEFENSE:
For forwards, the readiest (although crude) measure of defensive responsibility probably lies in the +/- figures, where Thornton boasts a distinct advantage over Savard careerwise (+51 vs. -54), but this season Savard is actually +4 and Thornton -5. As far as other stats go, Thornton has 17 Takeaways to Savard's 12, but then Thornton has 28 Giveaways to Savard's 12 (although I'm not sure I'd put much stock in the value of Giveaways). In Blocked Shots, Savard has 9 to Thornton's 5.

OTHER:
Big Joe typically takes a few more penalties than Savard, but this year they're within 2 PIM of each other. On faceoffs, performance is nearly identical as well (53.5% vs. 53.3%).

Basically, it would appear that these guys are pretty close in their performance so far this season. Thornton seems to have come back to Earth a bit after a career 125-point season (Earth for him being 25-30 goals and ~100 points), whereas Savard seems poised to build upon his last two seasons of tallying better than a point per game if he can stay healthy.

So Rich, I wouldn't get too upset about some Boston writer comparing the two in a spiteful jab at "Jumbo Joe." I'd say that Savard is marginally outperforming Thornton so far this year, but this level of offensive production is new territory for him, and secondly, it's only November, so we've got a long way to go.

Close, but no cigar...

The axe fell on Trent Yawney today in Chicago, with Denis Savard taking over for now. At the start of the season, I picked Yawney to be the first head coach voted off the NHL island, but Ken Hitchcock and Gerard Gallant beat him to the unemployment office.

Friday, November 24, 2006

Which Teams Are Giving Up Those Juicy Rebounds?

Following up on our previous look at offensive rebound opportunities, it's now time to see which teams are locking down the front of the net, and which ones are rolling out the red carpet for opposing forwards to try, try again if their first shot doesn't succeed. We're looking at team performance here, as it seems to me that preventing rebounds is a joint effort. Goaltenders try to contain or at least manage them, and defensemen need to sweep them out of harm's way as quickly as possible, while tying up their opponent so they can't get a stick on the loose puck.

The table below shows Rebounds Allowed Per Game for the 2005-6 NHL Regular Season, as well as the numbers so far this season (through the 296 games as of November 19). The league averages were 1.8 rebounds per team per game last year, and 1.3 so far this year. Again, a rebound is here defined as a shot occurring within 5 seconds of another shot by the same team, from within 60 feet, without another intervening event. Top teams in each column are shaded green, and the bottom dwellers in pink. I've also included the Shooting Percentage for these rebound shots for the two seasons, to help give a rough idea of the overall impact from these numbers. For instance, if the Devils give up 1.16 more Rebound Per Game than the Red Wings (1.74-0.58), and the Shooting Percentage is about 27% on those shots, then you can "guesstimate" that rebound handling costs the Devils about a goal every third game defensively compared to Detroit, or about 25 goals over the course of the season.

So what do these numbers tell us? Well, for starters, the defensive dominance of the Detroit Red Wings is reaffirmed. Their mark of 0.58 rebounds allowed per game is far below the rest of the league, especially comparing them to the last-place New Jersey Devils, who give up 3 times as many rebounds per game! The biggest improvement year-on-year has been made by the Tampa Bay Lightning, who went from merely average to 2nd-best in preventing rebound opportunities. The Pittsburgh Penguins have made a similar improvement, but only raising them from "truly awful" to 3rd-worst in the NHL.

So does your favorite goalie need to attach flypaper to his leg pads, or does your defense need a knuckle-dragging, low-brow banger to keep opponents clear of the crease? Take a look below and write your local GM, I'm sure he'd be glad to hear opinions on the subject...

Click below to enlarge

Wednesday, November 22, 2006

Fighting the Good Fight In Front of the Net

Before heading out for the Thanksgiving weekend, I wanted to leave a tasty treat for all of you to snack on - a look at rebound opportunities. Especially in a close game, working hard for those extra shots can make the difference between winning and losing, and the battle around the crease can be one of the most exciting aspects of the game.

My criteria here involves looking at shots that occur within 5 seconds of another shot, and are taken from 60 feet or less, without an intervening faceoff or other event. In his seminal Shot Quality paper, Alan Ryder uses the filter of 2 seconds, and a max shot distance of 25 feet. The difference here is that I'm not concerned with the goalie's ability to stop this rebound shot, I'm interested more in how often these events are occuring. For the purposes of Shot Quality (and a goalie's ability to make a save), a slapper from 50 feet should be the same whether it came off a faceoff win or whether an initial shot came in, and the rebound was picked up and fed back to the point. For this analysis here, however, I'm trying to figure out which teams are getting those "second shot" chances.

For the 2005-6 NHL Regular Season, I tallied 4,420 rebound shots, making for roughly 1.8 per team, per game. For 2006-7 (through last Sunday's games), I've got 753, which across the first 296 games yields only 1.3 per team, per game. Today, I'll post the Rebounds For numbers for this year and last, hopefully over the weekend I'll put up similar numbers for Rebounds Against.

The table below shows Rebounds For per game, for 2005-6 as well as the present season, and the difference between the two. Top performers in each category are shaded green, bottom-feeders are shaded pink. What we see here is that Colorado and Vancouver have markedly increased their rebound opportunities, while the San Jose Sharks, Ottawa Senators, and Florida Panthers have created much fewer than last season. At the bottom of the list, you have an indicator of how bad the Central Division is outside of Detroit and Nashville. St. Louis, Chicago, and Columbus garner the least rebound opportunities in the league, and for the Blue Jackets, the margin is pretty large. Perhaps a factor in Gerard Gallant's firing was that his boys just weren't winning (or fighting?) the battles in front to score those tough goals.

Click the image below to enlarge.

Tuesday, November 21, 2006

Updating Top Shot-Producing Faceoff Men

Yesterday we looked at shot generation immediately after the faceoff on a team-by-team basis, so now it's time to look at some of the outstanding players. Since we looked at last season with a minimum of 100 offensive-zone faceoffs, we'll use 25 draws as our minimum for this year so far (yes, it's a small sample size, but most of our top ten had 45-60). Recall that the league average this season is for a shot within 5 seconds of an offensive-zone faceoff 7.21% of the time.

**Shot Generation After FO By Player**
Player	Faceoffs	Shots	Shot Gen %
Andy Hilbert, NYI	27	6	22.22%
Alexander Svitov, CBJ	45	9	20.00%
Stu Barnes, DAL	45	8	17.78%
Dean McAmmond, OTT	62	10	16.13%
Ian Laperriere, COL	45	7	15.56%
Jeff O'Neill, TOR	52	8	15.38%
Mike Zigomanis, PHX	47	7	14.89%
John Madden, N.J.	68	10	14.71%
Kris Draper, DET	49	7	14.29%
Matthew Stajan, TOR	57	8	14.04%
Yanic Perrault, PHX	36	5	13.89%

This table "goes to 11", because everyone knows that Yanic Perrault has a great reputation as a faceoff man, so I wanted to include him in the post.

As far as Rally Killers go, three players have taken the requisite number of offensive zone draws without generating any shots so far: Boston Bruin Wayne Primeau (37 FO's), Columbus Blue Jacket Mark Hartigan (35 FO's), and Detroit Red Wing Dan Cleary (38 FO's). Interesting names to note near the bottom of this list are San Jose's Joe Thornton (3 shots on 146 draws for 2.05%) and Tampa's Brad Richards (4 shots on 137 draws, 2.92%).

So remember, print out this post and take it to your next NHL game, so you can shout out helpful suggestions to the head coach as he ponders who to send out for that critical late-game faceoff...

Phoenix Coyotes in Second Place! (in something, at least...)

One of the pieces I did early last month looked at how often teams and players generated shots off of faceoffs in the opponent's zone. Since we've pretty much hit the quarter-pole of the 2006-07 NHL Regular Season, I thought I'd update those numbers to reflect how things are going so far. Overall, across 296 games played through Sunday night, there have been 10,822 non-neutral zone faceoffs, of which 780 saw the offensive team generate a shot within 5 seconds of the draw (7.2%). So how do the teams rank? Let's take a look...

**Shot Generation After FO By Team**
Team	2005-6	2006-7	Difference
Ottawa Senators	11.85%	10.14%	-1.71%
Phoenix Coyotes	6.89%	10.09%	3.20%
Detroit Red Wings	9.31%	10.08%	0.77%
St. Louis Blues	11.23%	9.97%	-1.26%
Dallas Stars	8.79%	9.61%	0.82%
Edmonton Oilers	12.45%	9.12%	-3.33%
Toronto Maple Leafs	9.96%	8.89%	-1.07%
Colorado Avalanche	9.93%	8.88%	-1.05%
Los Angeles Kings	9.49%	8.75%	-0.74%
New Jersey Devils	7.18%	8.20%	1.02%
Montreal Canadiens	12.59%	7.94%	-4.65%
New York Islanders	10.35%	7.42%	-2.93%
Buffalo Sabres	8.27%	7.31%	-0.96%
LEAGUE AVERAGE	9.09%	7.21%	-1.88%
Washington Capitals	9.48%	7.07%	-2.41%
Boston Bruins	10.10%	6.85%	-3.25%
Minnesota Wild	9.96%	6.78%	-3.18%
Calgary Flames	9.62%	6.71%	-2.91%
New York Rangers	8.71%	6.67%	-2.04%
Columbus Blue Jackets	10.28%	6.63%	-3.65%
Atlanta Thrashers	6.44%	6.01%	-0.43%
Chicago Blackhawks	6.40%	5.65%	-0.75%
Florida Panthers	9.88%	5.57%	-4.31%
Vancouver Canucks	8.57%	5.56%	-3.01%
Philadelphia Flyers	8.23%	5.54%	-2.69%
Anaheim Ducks	6.77%	5.37%	-1.40%
Pittsburgh Penguins	7.22%	5.21%	-2.01%
Tampa Bay Lightning	7.31%	5.14%	-2.17%
Carolina Hurricanes	10.77%	5.11%	-5.66%
Nashville Predators	7.52%	5.08%	-2.44%
San Jose Sharks	7.02%	4.95%	-2.07%

There you go, Coyotes fans! Coach Gretzky isn't doing a completely awful job, with the wondrous improvement in shot generation from his faceoff men. They've come from the dregs of last year's standings all the way up into second place, behind the Ottawa Senators (get off their backs, already). Now I know what some of you are saying - "well, the Coyotes are always behind, so they're always trying to get a shot off the draw." Maybe so, but they stunk up the Pacific Division cellar last year as well, and that didn't help them in this area. Another point of interest here is how shots off the draw are down as a whole around the league, by 1.88%. This will be worth watching over the rest of the season, to see if the trend continues.

So how significant are these differences between the best and the worst? Basically, each team gets approximately 20 offensive-zone faceoffs each game (18 so far this season). Given a separation of roughly 5% in shot generation between top and bottom, it looks like the best teams would get about one additional shot per game through effective faceoff play. Without going through all the gory details, if we make a further assumption that most of these shots are 40-60 foot slappers, they have about a 5% chance of scoring on average (yes, I'm not taking rebound opportunities into account here). Put it all together, and you get 1 extra shot per game, over an 82 game season, each with 5% chance of scoring, which yields about 4 extra goals. Similar talent on the defensive end in preventing shots by your opponent (which I'll post tomorrow), should also potentially reduce Goals Against by about 4 goals. Not the kind of stuff that makes or breaks a season, but it could result in a marginal victory or two, enough to make the difference down the stretch as teams vie for playoff positioning.

Monday, November 20, 2006

We'll get back to the stats shortly...

A few days ago, Eric McErlain over at Off Wing Opinion wondered if hockey on TV in the US would ever improve . Well, you have to give VS. solid marks for effort, with the debut of the RailCam in tonight's Avs/Stars tilt. They'll have some work to do integrating it seamlessly into the telecast, but it really does help bring the speed and flow of the game to life for viewers.

For example: starting at 17:48 of the 3rd, they switch to the RailCam as Mike Modano picks up the puck near his own blue line and leads a charge up ice. As he enters the offensive zone, we are basically looking over his shoulder at a Colorado defenseman in good position, so Modano leaves it for Trevor Daley who carries it into the corner with a defender trailing. He then feeds it back to Modano who is now behind the net, and as Modano tries to center it, Tyler Arnason picks it up for the Avs and heads back the other way. The RailCam simply follows the action and takes us along like a wingman for Arnason's rush until it ends with a Sergei Zubov hipcheck. For a full 20 seconds, the RailCam follows the rhythm of the game in a way we haven't seen before.

Now if they could add a Bryan Marchment knee coming out of nowhere to knock the camera off-kilter, they'd have it nailed.

Oh, and by the way. That 4th Sabres goal against the Lightning tonight is one of the prettiest goals I've seen since the days of the Russian Five.

Friday, November 17, 2006

Crank up the video machine

Inspired by a post over at Off Wing Opinion, I've added some videos from Blinx.tv on the sidebar. If they wreak havoc with your browser and detract from your browsing here, please leave a comment and I'll consider removing it. I just thought it was a nice widget to add to the page...

Break Up The Bruins, and Lay Off The Sens...

As we close the first quarter of the 2006-7 NHL Regular Season, there are some teams out there feeling great about their starts (Buffalo, Anaheim) and others that are feeling the heat over disappointing results (Philadelphia, Columbus, Ottawa). But today's question is, how much of this reaction is overdone? Which teams are likely to come back towards the middle, as the ups and downs of the long NHL winter take their toll?

The tool I'm using here is "PythagenPuck", as outlined by Alan Ryder of Hockey Analytics. The basic idea is that a team's winning percentage bears a close relationship to their Goals For and Goals Against (shocking, ain't it?). The formula is pretty strong, in that if I take the Goals For and Against for each team in the league over the last three years, it kicks out an expected winning percentage that is usually within 2 or 3%, excluding the points from Shootout Wins (i.e., it would predict a .568 win percentage for San Jose last year, against an actual result of .604, or .598 if you back out extra points earned from shootout wins). I've backed out points from Shootout Wins because, being separated from the regular game action, that's probably worthy of it's own analysis, which I won't get into here.

Where I'm headed with this is that there are some teams out there right now whose winning percentage is remarkably higher or lower than PythagenPuck would predict based on Goals For and Against, meaning that it is likely that they'll see some correction over the course of the next few months and come back towards the norm. They've benefitted from (or been victimized by) some lucky bounces so far, and perhaps things aren't as rosy (or as bad) as they appear.

The table below shows the gap between actual winning percentage and the PythagenPuck prediction for each of the last three full seasons, along with this season so far. The top "overperforming" teams have been highlighted in green, while the underperformers are shaded pink. For example, in 2002-03, Calgary outperformed the prediction by 0.064 (a win percentage of .457 against a predicted .393). Average gaps for each season are listed below, and the sort is by this year's gap, starting with the biggest underperformer (Ottawa) and ending with the biggest overachiever (Boston).

Next we have the current (as of Friday, November 17) winning percentage and points pace for the 2006-07 Regular Season, excluding points from Shootout Wins. Last year, teams earned anywhere from 1 to 12 extra points in the standings from shootout victories, but your guess is as good as mine as to how that will shake out this year. And if I was a GM, player, or fan, I wouldn't be counting on shootout victories to get my team into the playoffs.

The "Return To Normal" column reflects what PythagenPuck would predict for each team for the whole season, bumped up by the average gap as shown at the bottom for 2006-07 so far (0.019). I'm putting this in there because over the last few years the league-wide average gap has been slightly above zero, and I wanted to reflect that in this season's projections. What would make the most sense here would be to revise the P value in PythagenPuck (see page 11 of Ryder's paper Win Probabilities) for the "new NHL", but this is close enough for blogwork.

"Implied Points Result" shows the points in the standings each team would gain if they finish the season at the "Return To Normal" win percentage. The big assumption here is that current Goals For and Goals Against trends continue for each of these teams. If Brian Leetch and Jason Allison sign with a team and start pounding out goals, then that team's PythagenPuck prediction would change correspondingly.

So in the end, what do the numbers here tell us? Well, at first glance, it looks like the pressure in Ottawa is a bit overdone. Their gap so far this year is staggeringly negative. In fact, they've actually scored more goals than they've given up, so over the long haul they should pop back up over .500. And if they can improve their GF/GA, the jump should be even more dramatic. They're really the only team that is significantly underperforming in the W/L column.

As for overachievers, we have three leading contestants. New Jersey, Nashville, and Boston are all racking up more points than would normally be expected. For the Devils, that means they may end up fighting just to make the playoffs unless things turn around. They're fortunate to have a winning record while having given up more goals than they've scored. Nashville still looks like a strong playoff team (but not necessarily a 100-point squad), and Boston looks like even a bigger mess than we thought. Yes, Bruins fans, you do have something to be thankful for next Thursday as you carve up that turkey - a .500 record for a team that gives up 4 goals for every 3 it scores.

Click picture to enlarge

Tuesday, November 14, 2006

Lies, Damn Lies, and Statistics...

There's been a lot of discussion lately regarding a study that was cited in Canada's National Post that argued that, among other things, Major Penalties help NHL teams win hockey games. There was an obvious "yeah, right" reaction from much of the blogosphere, and Sisu Hockey has done a nice evisceration of this shoddy piece, but I thought I'd put my thoughts in as well. What we really have here is another sad example of the media picking up a study and running with it before giving any kind of thorough vetting. So let's take a look inside...

Abstract: In the past few years, the National Hockey League (NHL) has struggled financially. Teams within the NHL and the league itself have been struggling to make money, and last year the NHL season did not take place because of a labor dispute and resulting lockout between the players and owners. Therefore, this makes the NHL a very appropriate target for study. As previous research on various professional sports and the NHL have shown that winning teams are going to draw more fans, determining what makes NHL teams win games is a worthy endeavor. This study does just this. By using Ordinary Least Squares regression and a data set compiled on numerous individual and team statistics for the 1999-2000 through the 2003-2004 seasons, this study determines the various factors that contribute to Team Point production and Goals Allowed in the NHL. Of special note is the finding that Major Penalties, most commonly assessed for fighting, do in fact help NHL teams win games. Hopefully by seeing what aspects of the game lead to NHL team success, the league can determine how to draw more fans in order to make more revenue.

First of all, I'd give these guys a "D" for writing. I know my high school English teacher would have scratched more than a few red lines through this part. But enough about style, let's get to the meat...

I. INTRODUCTION
Right now the National Hockey League is in an interesting position.

What position is that? Does it involve stirrups or something? Sorry, another snipe at their inept writing. I'll try not to keep harping on this.

The ultimate goal of these new regulations is to draw more fans to NHL games in order to make more money. In the 2002-2003 season 50% of the NHL’s revenues came from ticket sales, and an additional 30% came from in-arena sales. Thus, 80% of the league’s revenue can be traced directly back to the fans. If the NHL can increase attendance throughout the league, the individual teams and the league itself should make more money.

I believe this falls into the "No Shit, Sherlock" category.

Now, as the NHL has made these adjustments to bring more fans to the games, fans also want to see their team win. As numerous studies have shown, attendance at professional sporting events is significantly impacted by a team’s success.4 Better teams that win more games are going to draw more fans, and they are going to gain more support off the playing field as well. Sports teams are profitable entities and a winning record is an important factor in determining their financial success.

More "No Shit, Sherlock", except for that last sentence. I thought the whole point here is that, by and large, NHL teams are not profitable. And it should be noted that a winning record can be important for an individual team's profitability, but not for the league as a whole. For every winner, there's a loser...

II. CURRENT RESEARCH ON PRODUCTION IN SPORTS AND THE NHL

Here follows a largely irrelevant section surveying various studies across baseball, football, basketball, and hockey, none of which really get to the point about the factors that drive NHL team performance. The hockey ones are mostly about wage structure and its relation to ethnicity or violent play.

III. THE EMPIRICAL MODEL AND DATA

Here's where we enter the morass...

As wins and win percentage have often been employed in production models dealing with professional sports, the NHL does not base their rankings on either of these measures. In contrast, rankings in the NHL are determined by Team Points, where each team receives two points for a win and one point for a tie after regulation.

Obviously the authors don't understand that Team Points are equivalent to Win Percentage * Games Played. And another writing criticism; that first sentence is really awkward. Try starting it with "Although", rather than "As".

For some reason, they decide to focus on deriving two measurements for team performance: Team Points and Goals Allowed. Maybe it's just because those are the numbers that best worked out for them, but one would think that Goals For would be the natural complement to Goals Allowed, since the relation of Goals For and Against to Team Points has been fleshed out pretty well by numerous parties (including Hockey Analytics, for example).

As Sisu Hockey notes, there follows a list of "independent" variables which are used in the analysis, but since they aren't truly independent, the findings are fatally flawed. For instance, in the calculation for Team Points, they use both Goals For and Shooting Percentage. Since Goals For/Shots = Shooting Percentage, those two variables aren't truly independent; the authors are clearly guilty of statistical incest here.

Assists
As hockey is a team sport, player cooperation is an integral part of the game. Thus, some aspects of teamwork should be included in the production model. Therefore, the simple statistic of Assists is included as an independent variable in the Team Points model. As Assists help Goals happen and Goals are going to help NHL teams win games, Assists are expected to have a positive effect on Team Points.

More 3rd-grade quality writing here, accompanied by some bass-ackward logic. From a statistical perspective, Assists don't "help Goals happen." It's the other way way around. You can't have Assists without Goals, and regardless, it's the Goals For figure that impacts game results, not how many assists a team tallied on those goals. Again, two commingled variables are being called "Independent" here, but aren't truly so.

Plus/Minus
A final variable that will be included in this analysis of NHL Team Production is that of Plus/Minus. This statistic is kept for each individual player and shows whether a player has contributed more to goals, or has been scored on more while he is on the ice. If a player is on the ice while his team scores a goal, a player receives a “plus.” If he is on the ice while the opposing team scores, the player receives a “minus.” These “plusses” and “minuses” are then tallied throughout the season to assess how well a player plays both offensively and defensively. A high, positive Plus/Minus statistic is one sign of a good player. This variable will be included only in the Team Points model, but is expected to have a positive effect in that equation.

First of all, they don't make the Power Play distinction regarding the Plus/Minus calculation, which leads to more speculation that the authors don't really know much about hockey. You could have a team that's above average at Even Strength, with lousy special teams, and their Plus/Minus will look much better than their win/loss record would indicate.

Another example of commingled variables is using PIM and the count of Major Penalties. Majors are a component of overall PIM, so including these together only muddies the waters further.

IV. REGRESSION RESULTS
Here follows the outcome of this mish-mash. Two conclusions were cited in the National Post article regarding Major Penalties - "For each penalty minute served, a team accrued 0.07 points and decreased their opponent's scoring by 0.24 goals."

First, I believe they mistate the numbers in the paper, which refers to the Number of Majors, not the number of penalty minutes served. The coefficient for Majors to Team Points is indeed 0.07587 in this study. What the National Post overlooks is that if you're going to take a Major, you also need to account for the 5 PIM, which has a coefficient of -0.01087, so the net result (even using the paper's shoddy analysis) would be 0.02152, much less than was cited. As for the impact on opponent scoring (0.24 Goals Against reduction per Major), I just don't see that in here. The only table included regarding Goals Against uses logarithmic data, so perhaps I'm missing something.

By and large, the numbers match up with amazing precision and seem to point to some radical results. But that's really because they were hopelessly intertwined to begin with.

V. CONCLUSIONS
The real firebomb is right here:

As MAJORS were found to have a positive effect on PTS and a negative effect on GA, this implies that Major Penalties (more specifically fighting) do in fact aid a team’s success.

First of all, there is nothing in the study that suggests that fighting majors have any different effect than other major penalties. The authors are making an unwise leap here.

Even though fighting results in a penalty, it is shown to be able to jump start a team into action and elicit better play. For example, if a team is not playing well, a player might start a fight with the opposing team in order to get the momentum of the game back on his side.

Again, there is no evidence in the study to suggest this. They certainly don't look at event sequencing, to see if teams score goals after taking major penalties, or instead take those penalties once they have a safe lead.

My Conclusion
Overall, this looks like something an undergrad would put together, as an exercise in how to build a statistical study around a topic of their choice. Then the professor would rip it apart and send them back for better data to work with before drawing such assertive conclusions.

The work I do here in this blog isn't as formal as these authors are trying to be, in part because I think at this stage the interesting work lies in identifying fruitful areas for future study. Papers like this only serve to cast a disparaging light on the work of hockey statisticians in general, by publicizing absurd claims which fly in the face of both common sense and critical judgement. I'm an economist by training, but I wouldn't jump to use the economist's toolbox in this field before I truly felt confident that the source material is valid, and that the results would be useful. This study fails in both those areas.

Monday, November 13, 2006

Marching Into The Box

Today I thought I'd highlight some of the top penalty specialists of the 2005-6 NHL season. No, not penalty killing specialists, but instead those guys who took the most penalties of various kinds. The Syracuse Bulldogs had the infamous Tim "Dr. Hook" McCracken, a master at using the blade of his stick on anything but the puck, but who deserves that tag in the NHL? Here's a quick look at some of the leading practitioners of hockey's Dark Arts:

Chairmen of the Boards:
Vitaly Vishnevski (then with Anaheim, now with Atlanta) and Brooks Orpik of Pittsburgh led all players with 4 Boarding penalties, each with 3 minors and a major.

That Belongs in the Summer, Not Winter, Olympics:
Diving is always a hot-button issue in heated rivalries, and last year's Diving Champion was Atlanta's Ilya Kovalchuk with 4 Diving penalties. Coming up behind him with 3 each were Washington's Dainius Zubrus, Buffalo's Maxim Afinogenov, and Minnesota's Marian Gaborik. I'm sure Don Cherry would have nothing to say about all these guys being of European origin...

Credit Card Junkies:
The Rangers' Ryan Hollweg led all players with 5 Charging penalties (4 minor, 1 major), in only 52 games. Somebody get a handle on this kid! In a 3-way tie for second place, Jarkko Ruutu (then with Vancouver, now with Pittsburgh), Derek Boogaard of the Wild (no nose-picking jokes, please, he might read this), and Nashville's Darcy Hordichuk tallied 3 charging penalties apiece.

Stop That, You'll Go Blind:
After more than a decade in the league, you'd think that L.A. King Craig Conroy would learn that you can't close your hand on the puck. But he was nailed twice last year on this call, more than anyone else in the league. Some guys just can't help themselves, apparently.

No, This Doesn't Mean Hasek's Angry:
So who led the league in Cross-Checking last year? None other than 21-goal scoring defenseman Mathieu Schneider of Detroit, an 8-time offender. Four other players were next up with 6 infractions apiece.

There's No Alley-Oop In Hockey:
One of the recent rule changes is the Delay of Game call for shooting the puck over the glass. Former New York Islander (now L.A. King) Brent Sopel tied with former Wild (now Tampa Bay Lightning) Filip Kuba for sending 5 free souvenirs into the stands, and putting their own team a man down.

Annoyed By The Trapezoid:
Another rule change has the goaltenders required to play the puck within a trapezoid behind the net - puckhandling outside of that zone is a minor penalty. The always entertaining Dominik Hasek led all netminders with 5 offenses here (in only half a season!), with Curtis Joseph right behind with 4.

You Ain't No Gordie Howe:
Former Oiler now Duck Chris Pronger led all players with 4 Elbowing penalties last season. I certainly wouldn't want to see him out on the dance floor at a wedding doing the Chicken Dance...

Just Give Peace a Chance:
Perhaps the most coveted and revered penalty specialist is the Fighter, that Righter of Wrongs who steps in to defend his teammates and restore the balance of justice in what is often a cruel game. Former King (now Avalanche) George Parros tied with Ottawa Senator Brian McGrattan with 18 fighting majors last year. They also tied with scintillating 2 goal, 3 assist offensive efforts.

Hit The Showers Already:
Something must have honked off Eric Cairns when he was traded from Florida to Pittsburgh last year, as he racked up 3 Game Misconducts in a mere 27 games wearing the gold & black, tying professional pest Sean Avery of the L.A. Kings for the league lead. Maybe he had a favorite shower stall he wanted dibs on...

Keep Your Blade On The Ice, Boys:
Some guys put their money where their mouth is, and some would rather put their stick where YOUR mouth is. We had a three-way tie for the top High Stick practitioners: Micheal Nylander of the New York Rangers, Jaroslav Spacek now with Buffalo, and Mathieu Dandenault in Montreal.

Wilson Phillips Ain't Hockey Music:
So who couldn't help Holding on to their opponents? That would be Andreas Lilja of Detroit, who kept on huggin' to the tune of 17 holding penalties last year. Ruslan Salei (formerly of Anaheim, now with Florida) was next with 15 illegal clutches.

Dude, Watch the Hands:
It's bad enough to hold your opponent, worse yet to just reach out and hold their stick. Former Canuck Todd Bertuzzi couldn't keep his mitts off of opposing lumber the most last year, getting whistled 6 times. Nashville Predators Ryan Suter and Martin Erat were next with 5 and 4 penalties respectively.

This Ain't Fishin', Pal:
Sometimes when you get tired of skating it's easier to just hook an opponent with your blade and coast along for the ride. That's what Pittsburgh's Sergei Gonchar did more than anyone else last year, getting caught 25 times for Hooking, well ahead of 2nd place Jan Hrdina of Columbus with 20. At least he led the league in something for $4.5 million, right?

Somebody Get This Guy A Ruler:
When it came to illegal blades, New York Ranger Jaromir Jagr got caught twice with an overly wicked curve, the only player to do so more than once. With this year's change allowing extra curvature and adjusting the challenge rules, I'll bet we'll see this pop up even less than it did before.

Let's Get It Started:
Sure, lots of guys fight in the NHL, but apparently very few of them start fights. Veteran defenseman Sean O'Donnell tied with Duvie Westcott of Columbus with 3 Instigator penalties apiece. Maybe they just lack the rhythm to drop their gloves at the same time as the other guy...

What, He Didn't Have the Puck?
The NHL has made a lot of noise about cracking down on Interference in the last few years, and apparently old man Chris Chelios of the Red Wings needs to turn up his hearing aid. He got called for 11 Interference penalties last season, narrowly beating out Brendan Witt (last year with Washington and Nashville, now with the New York Islanders).

You Don't Belong In The Crease:
Nobody bulldozed the goaltenders more than Dustin Brown of L.A. and Todd Bertuzzi, who got called for Goaltender Interference 6 times each.

Bow Wow Wow:
When it came to Roughing, nobody came close to Jarkko Ruutu, who led the league with 20 Roughing calls. Add that to his near league-leading Charging performance, and you've quite the versatile offender. Ottawa's Chris Neil came in 2nd with 15 such penalties.

This Ain't D&D, Bub:
Brendan Witt apparently wasn't content with interfering with players, he also wanted to hack their limbs off, taking 12 Slashing minors last season. Chris Chelios was up next with 7 mighty swings, followed by a host of of others with 6.

Get 'Em An Abacus:
When it came to outstanding team efforts at taking penalties, the L.A. Kings led all squads with 16 Too Many Men calls. Washington, Atlanta, Montreal and Florida were all next with 11, so L.A. must have something real special going on there.

What Is This, Woodstock?
Tripping was a league-wide concern last year, with four players getting whistled 11 times for sending opponents on a long, strange trip - Toronto's Bryan McCabe, Nashville's Dan Hamhuis, Brendan Witt, and San Jose's Mark Smith. Just look at Smith's hair, does that look like the product of a stable mind?

You Ain't The Boss, Kid:
There would seem to be something to the criticism of Sidney Crosby that he whines too much to officials, as he was pegged with a league-leading 6 Unsportsmanlike Conduct penalties last year. Donald Brashear came in next with 5. Maybe if he played with a pacifier in his mouth, the ref wouldn't hear him. Hey, it's just a suggestion...

Friday, November 10, 2006

And Now For Something Completely Different...

While running some analysis on penalty information from last season, it struck me that after the addition of the Rocket Richard Trophy to the NHL's awards list, there was a terrible omission made that the hockey leadership needs to correct before it's too late. They need to stand up and recognize those pivotal players who perform a unique, critical role in the course of a game.

Yes, I'm talking about the guy who goes and sits in the penalty box for someone else (usually the goalie), the Server of the "Penalty Served By" in the boxscores. Sure, it can be somewhat akin to those painful schoolyard memories of youth, as the team has to select an on-ice player to sit in the box for a short time and "feel shame" for someone else's transgression. But someone's gotta take a breather for the team, and last year, nobody did that more often than Jonathan Sim, who sat through 14 extra penalties for the Flyers and Panthers.

Other standout sit-down artists? Jason Spezza of Ottawa took 12 extra rests, Toronto's Tie Domi took 10, and from there on down you have a host of others tied at 9, 8, 7, etc.

I'll have to track this one throughout the season, and of course come up with a fitting title for this coveted award. The Mannequin Cup? The Sin-Bin Salute? Feel free to submit your suggestions...

Wednesday, November 08, 2006

Is It Better To Give Than To Receive?

Previously we've looked at the team-by-team level of Hitting in the NHL, and shown that a high level of hits doesn't necessarily correspond with team success. I thought I'd take this a step further, and look at not just who's doing the hitting, but who's getting hit. The first table below shows accumulated data from the 2005-6 Regular Season, broken down by Hits For, Hits Against, the Ratio between those two values, as well as the difference (call it a Hits Plus/Minus). Not surprisingly, some of the teams that did the most hitting got hit the most as well, meaning that teams like Toronto, Ottawa and Dallas provoked other teams to hit back, responding to their aggressive play. Similarly, low-hitting teams like Minnesota, Florida, and Columbus were among the teams that got hit the least - their games were closer to the Ice Capades than SlapShot.

On the extremes, however, you have teams that either got hit or out-hit their opposition by a wide margin. The Boston Bruins, for example, dished out 44% more hits than they took, far ahead of 2nd-place Anaheim at +20% (hey, at least they led the league in something, right?). At the opposite end you have more teams that were seriously pushed around. Minnesota, Tampa Bay, Colorado, and the New York Rangers all gave less than 80% as many hits as they took, with the Rangers taking 378 extra hits over the course of the season. Take a look at the table below, and see how your favorite team stacks up on the Bully-to-Punching-Bag scale:

**Hits For and Against By Team (2005-6) Sorted By Ratio**
TEAM	HITS FOR	HITS AGAINST	RATIO	DIFF
BOS	1758	1222	1.44	536
ANA	1246	1041	1.20	205
PIT	1321	1161	1.14	160
NYI	1523	1341	1.14	182
CBJ	1147	1011	1.13	136
WSH	1542	1360	1.13	182
FLA	1121	996	1.13	125
TOR	1805	1613	1.12	192
CHI	1351	1230	1.10	121
N.J	1167	1067	1.09	100
OTT	1758	1611	1.09	147
MTL	1649	1520	1.08	129
L.A	1353	1277	1.06	76
ATL	1406	1329	1.06	77
CGY	1648	1559	1.06	89
DAL	1722	1633	1.05	89
VAN	1355	1302	1.04	53
EDM	1203	1175	1.02	28
STL	1175	1175	1.00	0
PHX	1422	1435	0.99	-13
NSH	1155	1231	0.94	-76
S.J	1411	1518	0.93	-107
PHI	1294	1414	0.92	-120
DET	1149	1296	0.89	-147
CAR	1137	1283	0.89	-146
BUF	1073	1285	0.84	-212
COL	951	1209	0.79	-258
MIN	846	1106	0.76	-260
NYR	1192	1570	0.76	-378
T.B	975	1297	0.75	-322

Now here's where things get real interesting. We showed earlier that the level of Hits a team makes isn't significantly correlated to its performance. When you look at the correlation of Hits to Goals For and Against, you come up with values of -0.03 and 0.05, so near to zero as to suggest no relation between those figures. For those needing a quick refresher, correllation values swing from 1 to -1. 1 means that two stats run perfectly in lockstep, -1 means they are opposed (high value in one means low value in the other), and 0 means no discernable relation.

When I ran the figures for the Ratio of Hits For/Against on a team-by-team basis against their Ratio of Goals For/Against, I came up with something surprising; a correlation value of -0.40! That suggests that teams which outhit their opponents end up getting outscored by them (and hence, why Bobby Clarke is out of work).

The relationship isn't particularly strong, but it is stronger than many other links found so far. Perhaps the real heroes on a team are the guys who take Hits in order to make plays, holding onto the puck for that extra split-second before getting knocked on their kiester.

I'd encourage those who are more formally trained in statistics to verify these results (hello, Hockey Analytics and Hockey Numbers). And stay tuned for further nuggets from the NHL statistical goldmine...

**Hits For and Against By Team (2005-6)**
TEAM	GOALS FOR	GOALS AGAINST	RATIO	HITS FOR	HITS AGAINST	RATIO
ANA	254	229	1.11	1246	1041	1.20
ATL	281	275	1.02	1406	1329	1.06
BOS	230	266	0.86	1758	1222	1.44
BUF	281	239	1.18	1073	1285	0.84
CAR	294	260	1.13	1137	1283	0.89
CBJ	223	279	0.80	1147	1011	1.13
CGY	218	200	1.09	1648	1559	1.06
CHI	211	285	0.74	1351	1230	1.10
COL	283	257	1.10	951	1209	0.79
DAL	265	218	1.22	1722	1633	1.05
DET	305	209	1.46	1149	1296	0.89
EDM	256	251	1.02	1203	1175	1.02
FLA	240	257	0.93	1121	996	1.13
L.A	249	270	0.92	1353	1277	1.06
MIN	231	215	1.07	846	1106	0.76
MTL	243	247	0.98	1649	1520	1.08
N.J	242	229	1.06	1167	1067	1.09
NSH	259	227	1.14	1155	1231	0.94
NYI	230	278	0.83	1523	1341	1.14
NYR	257	215	1.20	1192	1570	0.76
OTT	314	211	1.49	1758	1611	1.09
PHI	267	259	1.03	1294	1414	0.92
PHX	246	271	0.91	1422	1435	0.99
PIT	244	316	0.77	1321	1161	1.14
S.J	266	242	1.10	1411	1518	0.93
STL	197	292	0.67	1175	1175	1.00
T.B	252	260	0.97	975	1297	0.75
TOR	257	270	0.95	1805	1613	1.12
VAN	256	255	1.00	1355	1302	1.04
WSH	237	306	0.77	1542	1360	1.13

Monday, November 06, 2006

Team By Team Opportunistic Turnovers

Late last week I reported on individual leaders from last season in terms of offensive chances generated from Takeaways and Hits, so now it's time to present the numbers on a team-by-team basis. What's interesting here is that some teams generated offense out of their hits and takeaways much more effectively than others. On average, 19.2% of Takeaways and 7.5% of Hits resulted in an offensive chance within 10 seconds (defined as a Shot, Goal, Blocked Shot, or Missed Shot). So let's take a look...

If you compare these results with the table here, which shows total Hits and Takeaways from the 2005-6 NHL season, you'll see some teams failed to generate much offense out of their physical game. The Boston Bruins, for example, had the 3rd-most hits in the league, but were near the bottom in offense generated, producing shots less than 5% of the time after making a hit. The Philadelphia Flyers, on the other hand, produced shots almost twice as often, jumping from 16th in the Hit rankings to 5th on the list here.

The story is similar regarding Takeaways. Tampa Bay was in the middle of the pack in terms of Takeaways, but dead last in chances generated from them. Instead of getting shots 19% of the time, they struggled below 12%. At the opposite end of that scale were the Ottawa Senators, who were 12th in Takeaways, but 3rd in offense generated from them, converting at a 22.45% clip.

**Offensive Chances Generated From Takeaways & Hits (2005-6)**
TEAM	TAKEAWAYS	HITS	TOTAL
Montreal Canadiens	213	113	326
Ottawa Senators	141	131	272
New York Islanders	129	133	262
Washington Capitals	128	130	258
Calgary Flames	129	117	246
Philadelphia Flyers	115	123	238
Atlanta Thrashers	132	104	236
Colorado Avalanche	165	68	233
Toronto Maple Leafs	82	147	229
New York Rangers	131	95	226
Detroit Red Wings	131	94	225
New Jersey Devils	139	85	224
Edmonton Oilers	123	99	222
Dallas Stars	106	115	221
Nashville Predators	113	99	212
Anaheim Ducks	120	90	210
Columbus Blue Jackets	115	86	201
Boston Bruins	112	86	198
Phoenix Coyotes	81	113	194
Carolina Hurricanes	113	77	190
Los Angeles Kings	76	110	186
Chicago Blackhawks	90	94	184
San Jose Sharks	83	101	184
Pittsburgh Penguins	84	98	182
Vancouver Canucks	82	100	182
Buffalo Sabres	96	82	178
St. Louis Blues	89	89	178
Florida Panthers	93	79	172
Minnesota Wild	103	56	159
Tampa Bay Lightning	72	67	139

These are just a couple elements that I'll be using in the coming weeks to provide detailed analyses for each of the NHL teams as we approach the quarter-pole of the 2006-7 season. It's about time for teams to start making roster moves as they realize that training camp dreams just won't work out (isn't that right, Flyers fans?), and a thorough look inside the numbers might help assess where each team truly needs some help.

Friday, November 03, 2006

Ranking the Game Changers

It happens about four or five times a game, and whenever it does, it brings the fans out of their seats - a big hit or takeaway that directly results in a scoring opportunity. The question is, who produces those signature moments? As a followup to the question of how Hits might impact Shot Quality and offensive production, I thought it would be interesting to find out how often Hits and Takeaways result in Shots, Missed Shots, Blocked Shots, or Goals within 10 seconds of the turnover. Data again comes from the 2005-6 NHL Regular Season Play-By-Play files.

I'm including Missed Shots and Blocked Shots here, as they are really the result of either a poor effort by the shooter or an outstanding effort by the opposing team, but either way these are unrelated to the value of the turnover generated by the player making the Hit or Takeaway.

Edit: Many thanks to Anonymous, for pointing out how to tighten up the table presentation.

**Top 10 in Offensive Chances Generated From Hits**
Trent HUNTER, NYI	30
Brendan MORROW, DAL	27
Dustin BROWN, L.A	24
Christopher NEIL, OTT	21
Arron Asham, NYI	20
Alexander OVECHKIN, WSH	18
Steve OTT, DAL	17
Shane DOAN, PHX	16
Dainius ZUBRUS, WSH	15
Donald Brashear, PHI	15
Michael RYDER, MTL	15
Jed ORTMEYER, NYR	15
Grant MARSHALL, N.J	15
Steve BEGIN, MTL	15

Check out last year's Calder Trophy winner, Alex Ovechkin! He's really the lone offensive superstar on this list.

**Top 10 in Offensive Chances Generated From Takeaways**
Scott GOMEZ, N.J	22
Daniel ALFREDSSON, OTT	22
Jason WARD, NYR	21
Mike MODANO, DAL	20
Saku KOIVU, MTL	20
Ryan SMYTH, EDM	19
Jason BLAKE, NYI	19
Marian HOSSA, ATL	18
Alexander OVECHKIN, WSH	17
Andrei MARKOV, MTL	17
Joe SAKIC, COL	17
Ilya KOVALCHUK, ATL	17
Ian LAPERRIERE, COL	17

A few dandies in here, more interested in swiping the puck than merely making a hit. Notice Ovechkin's the only player on both lists. And now, the totals...

**Top 10 in Offensive Chances Generated From Total Turnovers**
Trent HUNTER, NYI	41
Alexander OVECHKIN, WSH	35
Brendan MORROW, DAL	35
Christopher NEIL, OTT	30
Dustin BROWN, L.A	28
Shane DOAN, PHX	28
Michael RYDER, MTL	27
Arron Asham, NYI	27
Dainius ZUBRUS, WSH	26
Marian HOSSA, ATL	26
Saku KOIVU, MTL	26
Daniel ALFREDSSON, OTT	26

And finally, there's the most impressive play of all, when a player makes a Hit to take the puck and then scores a goal immediately afterwards. It's pretty rare, happening only 20 times last year. The only player to record multiple such feats was Lee Stempniak of the St. Louis Blues. To top things off, he made those plays in back-to-back games first against Detroit on February 1st, then against Chicago the next night. Maybe he he got hypnotized into thinking he was the second coming of Cam Neely or something - regardless, he's off to a good start this year with 10 points in his first 12 games.

Thursday, November 02, 2006

Crank up your calculators

There's a nice update to the Shot Quality analysis by Ken Krzywicki over at Hockey Analytics that's been posted recently, and update based on the 2005-6 NHL Regular Season data that I've been digging into here. Besides the previous work which looked at shot distance, shot type, rebound situation, and team strength, he's also added Shot After Turnover (based on Takeaways & Giveaways) as a factor in the analysis. It's well worth looking into, and since I was just going to start a similar line of analysis over here, I forwarded some questions over to Ken, which I'll include here:

1) Shouldn't empty-net goals be excluded from the model? The whole notion of shot quality presumes a goaltender on the other end attempting to make a save. For 2005-6 (based on PBP files) I show 7,428 goals, with 178 empty netters. That's around 2.5% enough, to tweak the margins a bit.

2) Should penalty shots be split out as a descriminating factor? Certainly the scenario is somewhat different than the rest of in-game action, and I show 35 penalty shot goals on 85 shots, reflecting a shot quality that is higher than mere distance and shot type would predict.

3) What to do about Missed Shots? While they shouldn't factor into goaltending evaluations, I would think they should certainly count against an offense. There are lots of defensemen with big slapshots that go booming off the endboards, and I would think those should be assigned a zero or near-zero Shot Quality. If you have two players with equal numbers, but one took twice as many Missed Shots as the other, I would think that should reflect in their Shot Quality. You could also give credit to a team defense for higher levels of Missed Shots (not giving opposing shooters enough time & space to shoot well).

4) When looking at Shot After Turnover, should a time constraint be used to ensure that the shot is somewhat related to the turnover? Realistically, after 5 or 10 seconds, the short-term effect of the turnover has pretty much passed as the rest of the players react. I would also add Hits into that filter (i.e. a Takeaway, Hit, or opponent's Giveaway followed by a shot within 10 seconds). For instance, right in the first game of the 2005-6 Regular Season, plays 2 & 3 show a hit by Patrice Bergeron of Boston, followed by a Hal Gill wrist shot 9 seconds later. You could argue that the Hit led to the shot just as surely as a Takeaway would.

Overall, this is a nice update to a very useful piece of analysis by the gang at Hockey Analytics. I've got a slightly different spin on the anlaysis which I hope to post here next week.