Thursday, July 31, 2008

Power Play +/-

Yesterday, I wrote about an on/off ice +/- for penalty kills and listed the best and worst players of last season under it. The next logical step is to apply the same system to power plays. This is exactly the same as the even strength on/off ice adjusted +/- except it is restricted to play on the power play. By doing this, we can look at the sabermetric problem of individual power play success. A player's on ice +/- rating (per 60 minutes) is compared to that of his team when he is off the ice. The credit for this idea goes to Gabriel Desjardins of behind the net.

In order to not complicate things, these numbers are only time spent on 6 on 4 power plays and include only players who have 60 minutes or more playing time in the situation. Because of the limited amount of time spent on the power play, the exact order of players is probably dominated by statistical noise (one more or less goal could move a player several spots on any list), but the method is good to separate the good and bad players on the power play. Here are the top 10 such players last season:

Top 10 Adjusted 5 on 4 Power Play +/- Ratings 2007/08
RankPlayerTeamOn Ice +/- Off Ice +/- Adjusted +/-Minutes 5 on 4
1Rostislav OleszFlo9.131.947.18144:29
2Michael NylanderWas7.070.816.26195:12
3Scott NiedermayerAna7.611.426.19181:26
4Ryan GetzlafAna7.561.995.14277:58
5Jere LehtinenDal9.884.334.76151:41
6Jason SpezzaOtt7.982.784.62308:34
7Daniel AlfredssonOtt7.702.754.52280:42
8Ilya KovalchukAtl4.510.004.51425:01
9Dany HeatleyOtt7.763.254.50293:56
10Jarome IginlaCal6.442.084.36335:23

Rostislav Olesz is a bit of a surprise leader. Florida did very well when he played on the power play last season. They would be advised to give him significantly more power play time in the future. Michael Nylander is next. He is a creative passer who excelled when given extra room. Next up are Anaheim Ducks Scott Niedermayer and Ryan Getzlaf (who also does very well in +/- at even strength). Jere Lehtinen is primarily known as a defensive forward, having won the Selke Trophy three times, but he also excelled on the power play. Ottawa Senators Jason Spezza and Daniel Alfredsson are next. Ilya Kovalchuk comes next. The Atlanta Thrasher power play depends on him so much that the team allowed as many shorthanded goals as they scored power play goals when he was not on the ice. Dany Heatley is a third Senator on the list, which is rounded out by Jarome Iginla. This is a very good group of offensive players who excelled on the power play in 2007/08.

On the flip side, here are the 10 worst players in 5 on 4 situations last year (with 60 or more minutes played):

Worst 10 Adjusted 5 on 4 Power Play +/- Ratings 2007/08
RankPlayerTeamOn Ice +/- Off Ice +/- Adjusted +/-Minutes 5 on 4
1Rene BourqueChi-0.865.19-6.0669:26
2Rob NiedermayerAna0.005.71-5.7163:58
3David BoothFlo2.427.71-5.30124:06
4Keith AucoinCar2.997.68-4.6980:11
5Francois BeaucheminAna2.166.66-4.50222:13
6Christian EhrhoffSJ1.765.94-4.18170:56
7Andy McDonaldStL2.036.12-4.09266:30
8John MaddenNJ0.864.90-4.0469:36
9Maxim AfinogenovBuf2.426.39-3.97173:02
10Devin SetoguchiSJ1.235.14-3.9197:14

This group of players is for the most part not known for offensive skills. Their failure on the power play is not too surprising. Rene Bourque leads the power play inept group. His team actually allowed more goals while he was on the ice on a power play than they scored. Rob Niedermayer makes the worst list in second place (while his brother Scott is on the best list). David Booth is next despite putting up a very good +/- at even strength (but in limited playing time). Keith Aucoin is next. He is followed by Francois Beauchemin. Anaheim's power play improved a lot when Scott Niedermayer returned allowing Beauchemin to not receive as much power play time. Christina Ehrhoff comes next. He is followed by Andy McDonald. McDonald's trade to St Louis got him off the Anaheim power play, which is another reason it improved around the time Scott Niedermayer returned. John Madden is the second player on this list that I would have nominated for the Selke. Being a good defensive forward does not include being a top player on the power play. Maxim Afinogenov is next. He had an all around awful season with a bad even strength +/- rating as well. Devin Setoguchi rounds out the list of the worst power play players last season.

On/off ice adjusted +/- ratings on the power play is a good way to rate individual success on the power play. There is significant statistical noise in the rankings because of the lack of time spent on power plays in a season. Nevertheless, the most successful power play players and least successful ones can easily be differentiated from one another.

Wednesday, July 30, 2008

Penalty Kill +/-

In this summer's sabermetrics and hockey posts I have been discussing +/- ratings so far. I have shown two ways to adjust +/- ratings between teams: one as a rate stat and one as a counting stat. One problem with this analysis that prevents meaningful sabermetric discussions of defence is that penalty killing is not included in standard +/- ratings. Penalty killing is an important defensive function and as such should be measured, but it cannot be done starting with a traditional +/- rating.

One solution, which is credited to Gabriel Desjardins at behind the net is to treat penalty killing situations exactly the same way you treat even strength ones when calculating an on/off ice adjusted +/- which I have been calling a rate stat +/- adjustment. Obviously, individual players will have worse on ice +/- ratings in shorthanded situations. They will also have worse off ice +/- ratings. In the end, the difference between the two can be used as a ranking.

The main problem is sample size. Players do not spend a lot of time penalty killing in a season. The effect of one goal on a player's ranking is significant, so exact player ranking order needs to be viewed with caution, but it should be easy to see who the best penalty killers and who the worst ones are.

In order to solve the inconsistencies of one and two man advantages (and 4 on 3 power plays), only 5 on 4 situations are included in these numbers. The others do exist, but are so rare that it is hard to gather any meaningful statistics from them. Only players who spent at least 60 minutes killing penalties are listed in these rankings. This removes the problem of a player who killed one penalty all season "leading" in the rankings and has us including only those players who played enough time to have somewhat meaningful statistics.

Here are the top 10 players in their adjusted short handed +/- rating last season:

Top 10 Adjusted 4 on 5 Penalty Kill +/- Ratings 2007/08
RankPlayerTeamOn Ice +/- Off Ice +/- Adjusted +/-Minutes 4 on 5
1Sergei ZubovDal1.34-4.936.27134:47
2Trevor LindenVan-1.20-6.365.1699:43
3Marc SavardBos-1.88-6.885.0063:38
4Dennis WidemanBos-3.43-8.164.73227:37
5Carlo ColaiacovoTor-4.80-9.384.5862:26
6Chris KunitzAna-1.60-5.784.1875:26
7Andrew CoglianoEdm-0.92-4.984.0665:36
8Lasse KukkonenPha-1.80-5.744.0699:38
9Alexei KovalevMon-2.19-6.123.93109:53
10Zdeno CharaBos-4.17-8.103.93258:43

This list is led by Sergei Zubov, who amazing was on the ice for more goals for than against while short handed. He is followed by Trevor Linden, who was a good penalty killer despite a dropoff in the rest of his game. Then comes Marc Savard, who is not known as a defensively responsible player. Dennis Wideman is another Boston player who comes next. Carlo Colaiacovo was a successful penalty killer for the Leafs. Chris Kunitz did a very good job in Anaheim, despite not being one of their more famous defensive forwards. Andrew Cogliano appears on this list as a rookie, which is a sign of maturity beyond expectation. Lasse Kukkonen shored up the Flyer defence on the penalty kill. Alexei Kovalev did well with Montreal and is not primarily useful as a scorer. Zdeno Chara is the final player on this list.

Here are the 10 worst adjusted penalty kill +/- ratings from last year:

Worst 10 Adjusted 4 on 5 Penalty Kill +/- Ratings 2007/08
RankPlayerTeamOn Ice +/- Off Ice +/- Adjusted +/-Minutes 4 on 5
1Mats SundinTor-13.27-5.44-7.8368:05
2Jason WardTB-8.73-3.32-5.41150:53
3Steve BeginMon-8.83-3.76-5.0788:26
4Steve OttDal-6.41-2.13-4.28168:38
5Jarred SmithsonNas-6.17-1.91-4.26204:07
6Andy WozniewskiTor-8.95-4.79-4.16107:02
7Bryan SmolinskiMon-7.68-3.64-4.04109:26
8Kevyn AdamsChi-7.12-3.16-3.9667:30
9Dave BollandChi-6.60-2.64-3.9672:32
10Jim SlaterAtl-9.39-5.46-3.9382:48

Mats Sundin may be a star at even strength, but he did not do well on the penalty kill. The remainder of the list after Sundin is not nearly as big name players. Jason Ward, Steve Begin and Steve Ott are next. Jarred Smithson makes this list and worst 20 at even strength. Andy Wozniewski, Bryan Smolinski, Kevyn Adams, Dave Bolland and Jim Slater round out the list of inept penalty killers.

One piece of being able to rate individual defensive play sabermetrically is rating play on the penalty kill. Although there are limited amounts of time spent killing penalties, making for significant noise in the statistics, this can be done using on/off ice adjusted penalty kill +/- ratings. This method is successful to differentiate good and bad penalty killers.

Tuesday, July 29, 2008

Bouwmeester Preparing To Leave Florida

Yesterday, Jay Bouwmeester signed a one year $4.875 million contract with the Florida Panthers. In the strange world of the NHL that means he is likely leaving Florida as soon as he can. Bouwmeester was a restricted free agent. Next year (at age 25 - since he has been in the NHL since age 18) will be the earliest time he can be an unrestricted free agent and chose the location where he plays. Next year will be the first time he has the choice to play somewhere other than Florida. The fact Bouwmeester signed a one year contract (and not a longer one) shows that he is looking forward to that unrestricted free agency date and planning to move to a different market.

It has long been rumored that Jay Bouwmeester is unhappy with the way the Florida Panthers are run. It is hard to blame him. The team hasn't made the playoffs since 2000 (he joined the team in 2002) and with their trade of Olli Jokinen, who was last year's top scorer, the playoffs don't seem on the likely horizon. Bouwmeester wants to go somewhere where he can win.

In all likelihood, there will be a Jay Bouwmeester trade around the 2009 trade deadline and he will be a hot free agent in the summer of 2009. It seems clear that this is his last season in Florida.

Here is TSN's story on the signing, which carries the ironic headine "Staying In Florida". It turns out that the fastest way for Bouwmeester to get out of Florida was to sign this contract with them.

Monday, July 28, 2008

Maltby And Draper Are Replaceable

The important thing that comes from hockey sabermetrics is the ability to draw conclusions about the game. Sometimes these conclusions are not widely held by the hockey establishment. I listed some of these conclusions in the thread my sabermetric philosophy. One of my conclusions was:

Kris Draper and Kirk Maltby are no longer as valuable players as most fans believe. Their even strength performance could be replaced by the Detroit Red Wings without too much trouble (and likely with a cost savings).

This led to a long argument in the comments with David Johnson of hockey analysis. When the discussion was completed, I believe we agree (for the most part). I have not laid out my entire argument to support this conclusion at any point in this blog, so I thought I would do it today.

One way to assess how successful a player is in their role with their team is by looking at their adjusted +/- rating. I showed two ways to do this: one as a rate stat and one as a counting stat. The methods have some fundamental differences, but for the most part tend to give consistent results that usually are consistent with what can be seen by watching the NHL games. I listed the 20 worst players for the rate stat adjustment. Kirk Maltby is 15th worst and Kris Draper is 16th worst. I also listed the 20 worst players for the counting stat adjustment. Here, Kirk Maltby is 8th worst and Kris Draper does not appear on the list (he is 37th worst in the NHL in the 2007/08 season). This is not a particularly good showing for either player. Maltby obviously has a worse showing. Both are on the ice for a good number of goals against and few goals for when compared to teammates. This might be explainable if they consistently faced extremely tough competition. However, behind the net shows that is not true. It is the frontline players Nicklas Lidstrom, Pavel Datsyuk, Henrik Zetterberg and Tomas Holmstrom who face the top quality of opposition (and all but Holmstrom are among the best adjusted +/- ratings.

When I look at the Detroit Red Wings, I see a team that is hard to improve. They are the defending Stanley Cup champions and favorites for next year. Players with poor +/- ratings would be good candidates to be replaced in an attempt to improve the team. This is especially true when these players are not big scorers. Last year, Kirk Maltby scored only 10 points (he has not topped 11 points in a year since before the lockout). Draper was a little better offensively. His totals fell to 17 points last year.

It is true that Draper and Maltby have reputations as good checkers. Kris Draper won the 2004 Selke Trophy. Draper and Maltby both represented Canada in the 2004 World Cup. That was yesterday. Maltby turns 36 this year. Draper is 37. They are well into the decline phases of their careers. A lot of fans are slow to recognize this decline because it is not easy to statistically show that their defence is in decline (although their offence is easily shown by looking at their point totals).

Draper and Maltby earn almost $2.5 million between them for this work. Its not huge salary money, but in a capped NHL where every bit counts, it would be nice to get more performance for this money. It isn't too hard to do this. There are many examples of players who made bigger contributions than either of these two who earn around their salaries (or less). There are players out there who could do this. It wouldn't be that difficult for Detroit to have found some this summer, had that been their desire. Worst case, they would get players who don't score and put up poor adjusted +/- ratings against moderate opposition but cost less. That savings could be used to upgrade elsewhere. There is a good chance, if the Red Wings select well, that they could find players who make a much bigger contribution than Draper and Maltby.

All of this is not saying that Kris Draper and Kirk Maltby are pathetic NHL players. However, they failed in their roles last year. They were by no means the biggest failures in the NHL, but they did not do well. Given their age, it is unlikely that will change. This would be a direction I would be considering if I was in Ken Holland's position as the Detroit Red Wings GM.

That said I understand why he isn't doing it. Detroit is a place that NHL players want to play. This is shown, in part, by their signing of Marian Hossa this summer for below expected market cost. They go this way in part by winning and in part by being loyal to their players who have been loyal to the franchise. As an example, last year they brought back Darren McCarty in his comeback despite the fact he had little value. Kirk Malty and Kris Draper have been very loyal to the Red Wings and the Wings are loyal to them. This loyalty helps to get them free agents at below market cost. Players know they will be treated well in Detroit. Accepting subpar performances from Draper and Maltby (who can always warm the press box if necessary) is worth it to be able to have increased ability to sign free agents at below market costs.

Detroit has players like Darren Helm and Ville Leino in the system who might take their jobs. They could have added another low priced free agent or two to challenge them.

When a player plays a 3rd or 4th line role on a team and puts up a poor point total and a adjusted +/- rating against moderate (but not strong) quality of opposition, they are expendable. Given their ages, it is unlikely that Draper or Maltby will bounce back in the future.

Naysayers would argue against the adjusted +/- stat. The players are being compared to other really good players on a really good team and thus come out looking bad by comparison. How would they look on a worse team, where they are compared to worse players? For the most part, they wouldn't likely look any better. It is possible that their adjusted +/- would be better in the rate case, but more than anything that shows that the rate adjustment is not so good at finding weak performances on teams where the off ice +/- rating is always poor. In the end it doesn't matter much. There are many examples of non-star players on good teams who put up much better adjusted +/- ratings then Draper or Maltby in similar roles (and often with more points scored). This would improve Detroit on the ice to acquire one (neglecting more intangible things like leadership).

Kirk Maltby is the more replaceable of the two. He brings less to the Wings than Kris Draper does, but neither are strengths for their team when they are on the ice. I imagine the Red Wings know this and are planning a further phase out of these two this season. Neither of them brings enough to the team to provide a contribution that is hard to replace on the ice. Given their age, this should continue to get worse over time. Given the fact they make more than the minimum salary (Draper especially) for minimal contribution, replacing them would free up salary space for the Red Wings to use in the future. Done properly, replacing Kris Draper and Kirk Maltby this season would be a very good move for the Detroit Red Wings.

Sunday, July 27, 2008

The Chicago +/- Anomaly

In this summer's sabermetrics and hockey posts, I have been writing about +/- ratings. I have shown two ways to adjust +/- ratings between teams: one as a rate stat using on and off ice performance and one as a counting stat. I have compared the top 20 players under both methods here and here. One of the larger discrepancies in this exercise comes with Chicago Blackhawk players. On the counting stat list, Duncan Keith rates fifth and Patrick Sharp rates 14th. However, the rate stat list does not identify either as nearly as exceptional. Keith is ranked 57th and Sharp 81st. Why is this? Why does one list not select their performances?

The problem is the rate stat compares +/- ratings when a player is on the ice to their team's performance when they are on the ice. On most teams, most players play a relatively well defined role where they play with roughly the same calibre of linemates against roughly the same calibre of opposition throughout the whole season. This well defined role helps in the identification of exceptional players (either good or bad) since it will have them more clearly contrasted with other teammates who played in other well-defined roles. In Chicago, teams did not keep their well-defined roles over the whole season.

At the beginning of last season, Chicago played Martin Havlat and Jason Williams as their top two forwards who garnered the most ice time. On defence, Duncan Keith, Brent Seabrook and Brent Sopel were the most heavily played defencemen fro a group of defencemen with few standouts. By the end of the year, Patrick Kane and Jonathan Toews were played most frequently as the top forwards. Patrick Sharp emerged as one of the top forwards and the number one guy in defensive situations, when early in the year he was just another forward in their depth charts. Keith and Seabrook had established themselves as the top defencemen on the team and were pulling in more minutes and tougher assignments than those they had early in the season. It was a season of upheaval for the Blackhawks. Nobody maintained a well-defined role throughout the season. Essentially, everybody played with everybody in all situations. What this does it makes everyone's off ice +/- approximately equal. When compared to players on teams with more well-defined roles, it makes it harder to identify exceptional performances on the team. Duncan Keith and Patrick Sharp had better off ice +/- ratings than players like Sidney Crosby, Jarome Iginla and Joe Thornton who played on significantly better teams.

The on/off ice adjustment fails to find the strong performances of Keith and Sharp. This is a failing of that system. It is more team-dependent to find exceptional performances. They can be lost because of anomalous situations occurring while a player is off the ice. Although one could argue a similar situation of anomalous performances where a player is off the ice could also create what appears to be an exceptional performance, when it didn't occur, this is a much harder proposition. It is far easier for a team to be average when a given player is off the ice than it is for them to be truly spectacular or awful when a player is off the ice without this situation being a meaningful measure of the player in question. Where there is an effect, is when we rank players failure to identify an exceptional performance or two will push other players up (or down) those one or two points in the ranking chart that would have been held by the unidentified player.

In an on/off ice +/- adjustment it is more possible to miss out on an exceptional performance because of anomalous circumstances making a player's off ice performance appear more average than it normally should have been than for it to create what appears to be an exceptional performance because of an anomalously good or bad off ice performance. As a result, some exceptional players can be lost in the on/off ice +/- adjustment. This happened in Chicago in 2007/08 where Duncan Keith and Patrick Sharp had very good performances, but were lost due to the upheaval in the Chicago Blackhawks roster which changed the roles of essentially everybody throughout the season and averaged out off ice performance numbers. Keith and Sharp had very good years, which were found by the counting stat method and missed (for the most part) by the rate stat.

Saturday, July 26, 2008

Worst 20 Adjusted +/- (Counting Stat)

In this summer's sabermetrics and hockey posts, I have been discussing +/- ratings so far. I have shown two ways to adjust them between teams. One treats them as a rate stat using on and off ice +/- ratings and another that treats them as a counting stat. I have shown the top 20 and worst 20 adjusted +/- ratings as a rate stat. I have shown the top 20 adjusted +/- ratings as a counting stat. Today, I will show the worst 20 +/- ratings adjusted as a counting stat.

Worst 20 Adjusted +/- Ratings 2007/08
RankPlayerTeamAdjusted +/- On/Off Ice Rank
1Radek BonkNas-30.85
2Dallas DrakeDet-21.82
2Daniel BrierePha-21.834
4Alexander SeminWas-20.812
5Patrick MarleauSJ-19.622
6Olli JokinenFlo-18.678
7Niclas WallinCar-18.43
8Kirk MaltbyDet-17.815
9Maxim AfinogenovBuf-17.618
10Jarret StollEdm-17.217
11Steve McCarthyAtl-16.040
12Adam BurishChi-15.87
13Marcel GocSJ-15.64
13Andrew FerenceBos-15.650
15Patrick SharpChi-15.481
16Sam GagnerEdm-15.297
17Jamal MayersStL-14.824
17Martin SkoulaMin-14.828
17Mike ComrieNYI-14.8214
17Mike ModanoDal-14.851

This list is limited to players who played 50 or more games for the same team last season. Craig Adams, who was number one on the rate list, does not qualify because he split time last year between the Carolina Hurricanes and Chicago Blackhawks.

The difference between the worst players in the NHL is much smaller than the difference between the best players. The bottom part of most NHL team's rosters is largely interchangeable with one another. There should be more variation among the worst +/- ratings found by different methods than there is at the top. The rate calculations tend to pick players who play checking roles on good teams. These players are not as strongly selected because they don't have as much total ice time as some of the top line players on their team and because the quality of opposition factor is not so strong in the way these +/- ratings are adjusted. Nevertheless, some of those players do appear on this list. Players who played top line roles, but struggled in them tend to be highlighted more on this list. These are often famous NHL players who had bad seasons and unless they bounce back should be given reduced roles in the future. Also, defencemen get in these rankings more frequently because their increased playing time helps them get larger +/- ratings.

Radek Bonk leads this group of worst adjusted +/- ratings. He is well out in the lead. He had a poor year in Nashville last season. Dallas Drake is again among the worst. A newcomer near the bottom, Daniel Briere is tied with Drake. Briere is a weak defensive player, who had a lot of ice time. Philadelphia would improve if they could reduce his even strength minutes with another good scorer (Simon Gagne?). Alexander Semin, Patrick Marleau and Olli Jokinen are more players who are scorers who are weak in their own zone and saw decreases in their offence last year. Niclas Wallin is the worst defenceman on this list. He is followed by a few members of both lists in Kirk Maltby, Maxim Afinogenov and Jarret Stoll. Steve McCarthy is a defenceman who makes this list next. Then come some more members of both lists in Adam Burish, Marcel Goc and Mike Fisher. Andrew Ference is another defenceman who makes this list, but not the previous one. Sam Gagner, who had a good rookie year but struggled defensively, is next. Jamal Mayers, Martin Skoula, Mike Comrie and Mike Modano end up the list. Comrie is the biggest drop from the rate list because his Islander team was bad when he was off the ice so it was hard for it to be much worse in terms of +/- when he was on the ice. Mike Modano is a big name former superstar in decline who struggled much of last season.

Missing from the rate list are Eric Godard, Mark Smith, Ryan Hollweg, Colton Orr, Trevor Letwoski, Vitali Vishnevsky, Kris Draper and Jed Ortmeyer. None of them come in with particularly good adjusted +/- ratings, but they do not come out as badly. In most cases it is due to less ice time than the players who replaced them.

This list of the worst players according to their +/- ratings adjusted as a counting stat gives a list of players who struggled in their roles last season. Unless there is reason to imagine that they will improve in the future (and there is in some cases - such as Sam Gagner) their roles in the future should be decreased. In some cases, the player in question will likely be out of the NHL soon.

Friday, July 25, 2008

Top 20 Adjusted +/- Ratings (Counting Stat)

In my sabermetrics and hockey posts this summer, I have been discussing +/- ratings. I have shown one way to compare +/- ratings on different teams using on and off ice performance and given the top 20 and worst 20 ratings by that method. I have also shown another method which treats +/- as a counting stat (total values over a season are important) instead of a rate stat (per minute values are important). There are also normalized to teams in different manners. This will lead to some discrepancies between the lists of top and worst players. It is useful to look at different problems in different ways. Different insight is gathered by doing this. The biggest difference between rating systems is that the counting stat includes more defenceman (who in general play more minutes and in more varied circumstance than forwards and thus get lost in a rate stat).

The first step to calculating adjusted +/- ratings as a counting stat is to determine the team values, which are essentially the zero point for a player on a given team. Here they are:

Team +/- Rating Adjustments 2007/08
Team+/- adjustment
Anaheim Ducks+4.4
Atlanta Thrashers-7.0
Boston Bruins+1.4
Buffalo Sabres+1.6
Calgary Flames+2.8
Carolina Hurricanes+0.4
Chicago Blackhawks+2.8
Colorado Avalanche+3.2
Columbus Blue Jackets-2.0
Dallas Stars+3.8
Detroit Red Wings+9.8
Edmonton Oilers-5.8
Florida Panthers-0.4
Los Angeles Kings-6.6
Minnesota Wild-1.2
Montreal Canadiens+2.4
Nashville Predators+0.2
New Jersey Devils+1.6
New York Islanders-6.2
New York Rangers+1.4
Ottawa Senators+5.6
Philadelphia Flyers-0.2
Phoenix Coyotes-3.0
Pittsburgh Penguins+3.8
St Louis Blues-4.2
San Jose Sharks+0.6
Tampa Bay Lightning-9.6
Toronto Maple Leafs-2.6
Vancouver Canucks+0.2
Washington Capitals+2.8

Most teams are not too far off from zero. There are some exceptions at both ends. The Detroit Red Wings lead the way at +9.8, followed by the Ottawa Senators at +5.6 and the Anaheim Ducks at +4.4. At the bottom of the pack is the Tampa Bay Lightning at -9.6, followed by the Atlanta Thrashers at -7.0 and the Los Angeles Kings at -6.6. Team +/- adjustments depend upon how the team did at even strength and thus power play success as in the Montreal Canadiens or shootout success as in the Edmonton Oilers is not included.

Using these team adjustments as a baseline here are the top 20 adjusted +/- ratings last season along side their ranking in the on/off ice adjustment. For the most part the same players are highlighted. Only players who played 50 or more games with one team are included.

Top 20 Adjusted +/- Ratings 2007/08
RankPlayerTeamAdjusted +/- On/Off Ice Rank
1Pavel DatsyukDet+31.25
2Nicklas LidstromDet+30.217
3Ryan GetzlafAna+27.67
4Dany HeatleyOtt+27.42
5Duncan KeithChi+27.257
6Johnny OduyaNJ+25.415
7Alexander OvechkinWas+25.216
7Viktor KozlovWas+25.23
9Jarome IginlaCal+24.28
10Jan HejdaCBJ+22.030
11Jassen CullimoreFlo+21.440
12Michel OuelletTB+20.64
13Jason SpezzaOtt+20.412
14Henrik ZetterbergDet+20.213
14Patrick SharpChi+20.281
14David PerronStL+20.21
17Mats SundinTor+19.619
18Douglas MurraySJ+19.422
19Jason ArnottNas+19.29
19Brendan MorrowDal+19.227

The lists are clearly not the same, but they tend to highlight the same players. Which list is better? It depends what you are looking for. If you want to know total +/- contributions this one is. If you are interested in per minute stats the other one is.

Pavel Datsyuk climbs a few points to lead this list. He is followed by teammate Nicklas Lidstrom. Defencemen do better on this list because they tend to have more playing time and thus will have higher ranks in total +/- than in per minute ones. Ryan Getzlaf and Dany Heatley are next. They did well on both lists. Duncan Keith comes fifth. He is the first new name. He fell significantly on the per minute list because of high ice time and because his teammates did well when he was off the ice (better than teammates of Ryan Getzlaf or Jarome Iginla for example despite being on a weaker team). Next up came Johnny Oduya and the Washington pair of Alexander Ovechkin and Viktor Kozlov and then Jarome Iginla. All are players who rank well on both rankings. In tenth and eleventh are Jan Hejda and Jassen Cullimore. They are two solid stay at home defencemen who missed out on the other top 20. Michel Ouellet drops to 13th due to decreased ice time. Next up are Jason Spezza, Henrik Zetterberg Patrick Sharp and David Perron. Spezza and Zetterberg are ranked approximately the same on both lists. Sharp climbs significantly to make this list. Perron drops from number one on the other list due to low ice time. Mats Sundin is next with approximately the same rank. Douglas Murray is another defenceman who climbs into the list. The list is rounded out by Jason Arnott and Brendan Morrow (who did not make the previous list). This is another group of players who overlap with the other list. The main difference is more defencemen make this one because they get better +/- ratings with increased ice time. There is an anomaly with Chicago Blackhawk players as they are ranked far lower on the on/off ice list than they are here. That deserves further discussion and will be saved for another day.

Missing from the previous list are Paul Stastny, Joe Thornton, Milan Michalek, Sidney Crosby, Shawn Horcoff and David Booth. All finish well in the pluses on both lists. Booth and Horcoff slip the furthest due to low playing time.

Adjusting +/- ratings in this manner as a counting stat is a useful way to pick out the best players in the NHL. It does a better job of highlighting defencemen who played well than the other method. It does not rate players who played very well, but in limited roles, as highly. For the most part, it highlights the same players as the other system.

Thursday, July 24, 2008

My Sabermetric Philosophy

Since summer is underway and hockey news is scarce I have embarked upon a series of posts on sabermetrics and hockey. So far this summer, I have been looking at +/- ratings and what information can be gathered from them, with an eventual goal of trying to rate individual defensive performances. When presenting simple models to interpret +/- ratings I have received comments here and here that point me toward more complex linear regression type models to try to determine these things.

I would argue that these models are not significantly better than those that I am presenting. They are more mathematically complex and may be satisfying to those who enjoy "exact solutions" (in as much as anything that comes from flawed hockey statistics can be exact), but it is hard to draw any more information from them than can be gathered from the more simple models I am presenting. Any model should be as simple as necessary to produce the results we are looking for (but no simpler).

One must keep in mind that the input parameters (the statistics) are flawed. Most events (for example goals) are only weakly correlated with all the players on the ice. When most goals are scored, some players on the ice were not directly involved. There will be a huge amount of statistical noise inherent in any numbers which can create significant error in even the most "exact" calculations.

Further, a complex linear regression model obscures the process with which we analyze the statistics. It becomes a "black box" into which we input our statistics and the computer crunches numbers to give us a solution. The question of how valid that solution is and where things may be distorted is not so easy to answer as in the case of a simpler model. At the same time, a good simpler model will give essentially the same results. It is more instructive and time saving to stick to the simpler models as long as they are reliable.

As examples of that philosophy, here are some facts about the NHL last season that the on/off ice adjusted +/- ratings have shown which I believe are reliable conclusions (despite not being widely held among NHL fans). With a much more complex linear regression model you would get the same conclusions out with less intuition about why you obtained that result.

Conclusion 1: Johnny Oduya is a very good defenceman who is a key to the success of the New Jersey Devils.

Conclusion 2: David Perron and Michel Ouellet are two players who performed very well last season in protected roles against weak competition and should have their roles increased.

Conclusion 3: Paul Stastny, Ryan Getzlaf, Jason Arnott and Shawn Horcoff all had strong all star level performances and are much more valuable to their respective teams than most fans realize.

Conclusion 4: Kris Draper and Kirk Maltby are no longer as valuable players as most fans believe. Their even strength performance could be replaced by the Detroit Red Wings without too much trouble (and likely with a cost savings).

Conclusion 5: Niclas Wallin had an awful season and was probably the worst defender in the NHL last season. He definitely does not belong in the NHL any longer (except possibly in a bit role).

These are not statements that are clear to most fans and I am sure that if you (for example) posted them in the appropriate place on hfboards could get people to call you crazy for making them, but they are clearly born out by sabermetric analysis. These conclusions (and others) come from relatively simple analysis and I don't think much more is gained (and some transparency is lost) by using a more complex model that requires some computation time to solve.

Wednesday, July 23, 2008

Another Way To Adjust +/- Ratings

Over the past few days, I have been looking at the sabermetrics and hockey problem of adjusting +/- ratings for on and off ice performance, the framework of which was developed by Gabriel Desjardins of behind the net. I have posted the top 20 and worst 20 players last season in these stats, in hopes of eventually addressing player's individual defensive values.

There are many ways to look at this problem and today, I plan to lay out the framework of another method. One of the flaws of the on/off ice adjustment is that it is a rate measurement and not a counting measurement. This allows for players who have limited roles against either high or low level of opposition to be rated in the top or bottom of the league ahead (or behind) those players who play significantly more minutes in much more varied circumstances. Nobody cares who scored the most points per minute, unless they also scored the most total points. Similarly there should be less interest in who had the best +/- per minute unless they played enough minutes to lead the league. In part, this problem prevents many defencemen from being in the top or bottom of the on/off ice adjusted +/- ratings since they usually play more minutes and in more varied circumstances than forwards. In fact, only Johnny Oduya and Nicklas Lidstrom made the top 20 ratings and only Niclas Wallin and Vitaly Vishnevski made the bottom 20. Defencemen are under-represented. One way to fix this is to treat +/- ratings as a counting stat and not a rate stat.

We still have the problem of how to normalize +/- ratings between teams. One solution is offered in the book The Hockey Compendium by Jeff Klein and Carl-Eric Reif. Jeff Klein can be found today writing on the New York Times hockey blog SlapShot.

The method is to find a team's +/- rating (we will use Detroit as an example). Last year they scored 252 goals. 81 were power play goals, so they scored 171 goals that will count toward +/-. They allowed 179 goals. 57 were allowed while shorthanded. This gives 122 goals that count toward +/-. The Detroit Red Wings have a team +/- rating of +49. Now there are five players on the ice at most times, so this rating is split between these five players. Dividing it by five we get a team +/- adjustment of +9.8 for the Detroit Red Wings last year. That is the baseline that all Red Wings players are compared to. On Detroit, Pavel Datsyuk had a +41 +/- rating, while Kris Draper had a -2. After adjustment, this gives Datsyuk a +31.2 rating (which is very good) and Draper has a -11.8 rating (which is not so great).

In the future, I will look at who are the top rated players and the worst rated players by this method in the future and compare them to the on/off ice adjusted players to see exactly where the differences are and how meaningful they are.

Tuesday, July 22, 2008

Worst 20 On/Off Ice Adjusted +/- Ratings

Yesterday, I posted the top 20 on/off ice adjusted +/- ratings. This is an attempt to look at the sabermetrics and hockey problem of rating an individual player's defensive ability. I discuss the method here and credit Gabriel Desjardins of behind the net for its development.

I cannot argue that this method directly determines the best defensive player in the NHL. It will select players who played well in their roles, where their team played better with them on the ice than with them off the ice. These players will be offensive and defensive stars (most are solid two-way players).

In the comments Mathman criticizes it, claiming it tends to select good players on bad teams. I do not buy this criticism completely. In order to normalize +/- ratings to compare between teams, some assumptions must be made. The assumption made here is that the NHL is a parity-filled league. No team is really bad and no team is really good. The difference between the performance of a player while he is on the ice and and his team's performance while he is off the ice on his team would be roughly constant if a player was used in the same role on a different team. Given the weak link between a player's +/- and his ability (as he is often on the ice for goals he is not directly involved in), I think this is a reasonable assumption. I think it is no more problematic than using +/- as a starting point for this study. Obviously, other normalizations are possible and will give different results, but I do not think these differences are huge (at least in most cases).

The fact that 15 of the 20 players on the top 20 list come from playoff teams is strong evidence that it is not tiled toward bad teams. In fact they are under-represented if this list was a random list of teams. It shows that good teams tend to have good players - which agrees with common sense.

The specific example Mathman points out is Shawn Horcoff of the Edmonton Oilers, who makes the list in a large part because his team was awful when he was not on the ice. Horcoff is the player (who played 50 or more games last year) who has the worst off ice +/- rating. The fact he does not come from a team which can be realistically called the worst in the NHL (Edmonton finished 19th out of 30 teams last year) helps to show the model of a parity-filled NHL is a good one. It is probably not surprising that the player with the worst off ice +/- has a good adjusted rating in a parity filled league. The worst off ice +/- ratings are not all from one or two bad teams. They are spread out throughout several teams in the league. The player who's team played the worst without him on the ice is likely a valuable player to that team and likely to be one of the better players in the league. Of course, there are many questions that can be asked upon looking at the list. How would Shawn Horcoff have done on a better team? How would Milan Michalek have done if he didn't play with Joe Thornton? How would David Perron have done if he was played in a larger role in St Louis? These types of questions cannot be answered easily. They show one of the fundamental flaws in hockey sabermeterics. It is likely impossible to remove a player's contribution from his environment. This is a limiting factor in any kind of sabermetric argument.

Along with the top 20 players we can also look at the 20 worst players. These are players who struggled last season. They did not do well in their roles. In most cases, they neither scored well, nor played defence well. These are players who will likely see reduced roles in the upcoming season (if they don't wind up out of NHL jobs).

Top 20 On/Off Ice Adjusted +/- Ratings 2007/08
RankPlayerTeamOn Ice +/-Off Ice +/-Adjusted +/-
1Craig AdamsChi-1.96+0.74-2.70
2Dallas DrakeDet-1.30+1.16-2.46
3Niclas WallinCar-1.32+1.09-2.41
4Marcel GocSJ-1.66+0.71-2.37
5Radek BonkNas-1.61+0.63-2.24
6Eric GodardCal-1.56+0.59-2.15
7Adam BurishChi-1.48+0.45-1.93
8Mark SmithCal-1.19+0.71-1.90
9Ryan HollwegNYR-1.26+0.59-1.85
10Colton OrrNYR-1.36+0.48-1.84
11Trevor LetowskiCar-1.18+0.57-1.75
12Alexander SeminWas-0.96+0.79-1.75
13Vitaly VishnevskiNJ-1.03+0.67-1.70
14Jerred SmithsonNas-1.20+0.48-1.68
15Kirk MaltbyDet-0.82+0.79-1.61
16Kris DraperDet-0.30+1.27-1.57
17Jarret StollEdm-1.58-0.04-1.54
18Maxim AfinogenovBuf-1.04+0.50-1.54
19Mike FisherOtt-0.80+0.73-1.53
20Jed OrtmeyerNas-1.07+0.40-1.47

A quick look at this list shows that Mathman's complaint about the top 20 list is better suited for the bottom 20 list. This list is primarily filled with players on playoff teams. Those six who did not make playoffs were on some of the better teams that missed the playoffs (two Chicago Blackhawks, two Carolina Hurricanes, one Edmonton Oiler and one Buffalo Sabre). Every player on this list played for a team that had a positive +/- rating when he was off ice except for Jarret Stoll (who was barely a minus at -0.04). This somewhat confirms the talent structure in the NHL. There are a few best players. Most come from the best teams in the NHL. That is why those teams are the best. At the bottom of the NHL talent pool are many players who are roughly interchangeable with one another. Those who are used in tough checking roles on good teams who are not particularly good players will be on the bottom of this list. That is almost the entire list. There are a couple players who are nominally scorers, who did not score particularly well who also make the list. This list identifies some of the players who most struggled in their roles in 2007/08 and thus may see reduced roles in the future.

Craig Adams ( who I had listed as the worst regular in the NHL at one point this season) does the worst on this list. He is followed by the retiring Dallas Drake and a rare defenceman in Niclas Wallin. Marcel Goc and Radek Bonk are next. Bonk is the first player who is nominally a scorer (in that he is not used in a checking role). Eric Godard, Adam Burish and Mark Smith are next. They are followed by New York Rangers Ryan Hollweg and Colton Orr ( who I picked as the worst regular player in the NHL last season). Next up is Trevor Letowski and then Alexander Semin. Semin is probably the best offensive talent on this list, but he fell to a disappointing 42 points last year and has never been considered a defensive talent, even when he is scoring. Vitaly Vishnevski is the second defenceman on the list (joining Niclas Wallin). He is followed by Detroit's Kirk Maltby and Kris Draper. These players were once valuable checkers (Draper won the 2004 Selke Trophy), but time is passing them by. Jarret Stoll is next, followed by Maxim Afinogenov (who is nominally a scorer, but his 28 points were a failure). Mike Fisher and Jed Ortmeyer round out the list.

This list is a group of players who did not have good 2007/08 seasons. Most of them played on pretty good teams, but were used unsuccessfully in checking roles against top competition. These are players who probably should have been used in reduced roles, given their effectiveness last season, but they may not be the worst players in the NHL. This +/- normalization method makes it hard to fall this far if you play on a bad team. There are other ways to look at the problem to try to find such players. I would imagine that the worst players are roughly evenly spread throughout the NHL. Each team's weakest couple players are roughly interchangeable. It is the top players that differentiate good from weaker teams. This list is too heavily slanted toward players on good teams, but I think the worst players in the NHL are likely found uniformly on both good and bad teams. There is nobody on this list that I would suggest was a good defensive player in 2007/08.

Adjusting +/- for on and off ice ratings is a valuable tool to understand the NHL. Like any number it is imperfect and those imperfections must be kept in mind. That said, the top players in their adjusted +/- rating were some of the best players in the role and the worst +/- rating belong to players who struggled in their roles. Their identification is valuable to planning the future of your team.

Monday, July 21, 2008

Top 20 On/Off Ice Adjusted +/- Ratings

My first attempt to address the sabermetrics and hockey problem of rating individual player's defensively is to look at +/- ratings adjusted to give the difference between +/- when a player is on the ice and off the ice per sixty minutes played (which is an idea popularized by behind the net). The top players will not necessarily be the top defensive players in the league. They are merely players who had their team do better (in terms of goals for and against) when they are on the ice when compared to when they are not. Thus these players might be offensive stars. These players might be players who were used in special situations (for example with top linemates or against weak opposition) that allowed them their success in this statistic. These players are all players who excelled in the role they played on their team. Those players on this list who are star players on their team are some of the best players in the league. The lesser known players generally excelled in their lesser roles and probably are able to handle increased responsibility in the future in their career.

I wouldn't put too much importance on the exact order of players on this list, as it is at best a weak correlation between a player being on the ice and his team scoring or allowing a goal in many cases. Often goals are scored when a player in not directly involved in the play. It is very easy to imagine any player's totals being shifted by five or more goals (this is less than one per month of the regular season) merely by chance. That kind of uncertainty on these calculations would be able to shift the order of the top twenty players in this adjusted +/- list significantly. What is important is which players are present. They are players who excelled in their roles with their teams last season. It gives us a glimpse at defence because there are players on this list who are not high scoring; they must have made this list with good defence. However, it is an incorrect interpretation to suggest that these players are the best defensive players in the NHL last year.

In order to have played enough for their numbers to be meaningful, I have limited this list to the 525 players (non-goalies) who played 50 or more games played in the 2007/08 season.
Top 20 On/Off Ice Adjusted +/- Ratings 2007/08
RankPlayerTeamOn Ice +/-Off Ice +/-Adjusted +/-
1David PerronStL+1.67-0.622.29
2Dany HeatleyOtt+1.68-0.482.16
3Viktor KozlovWas+1.56-0.602.16
4Michel OuelletTB+0.96-1.192.15
5Pavel DatsyukDet+2.20+0.152.05
6Paul StastnyCol+1.66-0.342.00
7Ryan GetzlafAna+1.60-0.321.92
8Jarome IginlaCal+1.47-0.431.90
9Jason ArnottNas+1.43-0.471.90
10Joe ThorntonSJ+1.35-0.541.89
11Milan MichalekSJ+1.34-0.551.89
12Jason SpezzaOtt+1.39-0.461.85
13Henrik ZetterbergDet+1.89+0.081.81
14Sidney CrosbyPit+1.41-0.381.79
15Johnny OduyaNJ+1.28-0.481.76
16Alexander OvechkinWas+1.23-0.511.74
17Nicklas LidstromDet+1.92+0.261.66
18Shawn HorcoffEdm+0.47-1.191.66
19Mats SundinTor+1.05-0.551.60
20David BoothFlo+0.92-0.661.58

We see David Perron as a surprise leader of this list. Perron was far from the best player in the NHL last season. But he excelled in a protected role with the St Louis Blues playing against weak opposition. Perron is ready to make a big step forward this season.

Next up is Dany Heatley of the Ottawa Senators, who is a very good two-way player and one of the better players in the NHL.

Third is Viktor Kozlov. I think it is likely a statistical fluke that he ranks ahead of teammate Alexander Ovechkin, though he does. He is a better two-way player than he gets credit for.

Next up is Michel Ouellet, who excelled in a sheltered role in Tampa where he was played against weaker opposition. It will be interesting to see where he fits on the team next year now that they have added several new forwards.

The next three players are stars who play very good two-way games in Selke Trophy winning Pavel Datsyuk, Paul Stastny and Ryan Getzlaf.

Next up are further players who were the stars on their teams in Jarome Iginla, the under-rated Jason Arnott and Joe Thornton.

Milan Michalek comes along with Joe Thornton in San Jose. They were linemates and usually played under the same circumstances.

Next up are NHL stars Jason Spezza, Henrik Zetterberg and Sidney Crosby.

Next up comes the top defenceman on the list (probably defenceman play in such a wide range of situations that it is hard to crack such a list) Johnny Oduya of the New Jersey Devils, who I called the NHL's most unsung hero.

He is followed by MVP Alexander Ovechkin and Norris Trophy winner Nicklas Lidstrom (the second defenceman on this list).

Next up are two players who were the stars on teams that missed the playoffs. They are Shawn Horcoff of the Edmonton Oilers and Mats Sundin, who last year was a Toronto Maple Leaf. The final player on the list played successfully against weak opposition. David Booth in Florida. He is ready for a bigger role next season.

This list is a list of twenty good NHL players who excelled in their roles last season. All are solid defensively, though they are not the twenty best defensive players in the league by any reasonable measure.

Adjusting +/- ratings for on and off ice rates is a useful method to identify some very good hockey players. These players are all responsible defensively, but this does not isolate defensive play. A player can make this list by being a top scorer. It is a start in finding good defensive players in the NHL. Players like Jason Arnott, Johnny Oduya and David Perron are among those isolated. They are on this list with well known NHL stars like Alexander Ovechkin, Sidney Crosby and Jarome Iginla. You wouldn't go wrong with any of these players on your team, but more work must be done to try to isolate defensive ability. This step starts down that path, but is a long way from completing the job.

Sunday, July 20, 2008

A Look At The NHL Schedule

The NHL schedule was released this week along with the usual grumping about how the schedule is hard on favorite teams. In order to get a better look at things, I decided to look at the schedule myself. A good starting point is the super schedule made by the forechecker.

I think the most meaningful check of the schedule is the number of times a given team is tired fro excess travel when compared to the number of times their opponent is. I define travel tired as any of the following:

1. A team is forced to travel one time zone in one day

2. A team is forced to travel two time zones in three days or less

3. A team is forced to travel three or more time zones in five days or less

This definition may not be perfect as it does not track within time zone travel, but it captures most of a team's travel.

Naturally, there is a big difference between East and West Conference teams as the East Conference is contained in part of the eastern time zone and the West Conference has teams in four different time zones. Here are the results:

West Conference Travel Tired Teams
Team# of Travel Tired GamesOpponent Travel Tired Games+/-
Anaheim Ducks2319-4
Calgary Flames1021+11
Chicago Blackhawks917+8
Colorado Avalanche1620+4
Columbus Blue Jackets2818-10
Dallas Stars1617+1
Detroit Red Wings1923+4
Edmonton Oilers1815-3
Los Angeles Kings2520-5
Minnesota Wild1322+9
Nashville Predators914+5
Phoenix Coyotes1920+1
St Louis Blues1514-1
San Jose Sharks2913-16
Vancouver Canucks2623-3

East Conference Travel Tired Teams
Team# of Travel Tired GamesOpponent Travel Tired Games+/-
Atlanta Thrashers75-2
Boston Bruins85-3
Buffalo Sabres440
Carolina Hurricanes45+1
Florida Panthers62-4
Montreal Canadiens57+2
New Jersey Devils52-3
New York Islanders35+2
New York Rangers43-1
Ottawa Senators59+4
Philadelphia Flyers74-3
Pittsburgh Penguins29+7
Tampa Bay Lightning83-5
Toronto Maple Leafs76-1
Washington Capitals49+5

Clearly, the West Conference teams have a much larger travel issue with travel. Most teams are roughly equal in terms of tired games played and those played by their opponents. The Calgary Flames have the best differential of tired teams facing them 11 more times than they are a tired team. The Chicago Blackhawks are next with 8 more tired teams facing them than they are tired. These are the teams that I argue receive the biggest benefit from the schedule. The teams that have are travel tired more often than their opponents are the San Jose Sharks who are in that situation 16 more times than their opponent and the Columbus Blue Jackets who are in that situation ten times. These are the teams that have the toughest year due to their schedule.

The East Conference teams do not have as big an issue with travel. The team with the biggest difference between tired games played and those of their opponents is the Pittsburgh Penguins. They have seven more games where their opponents are tired than they are. This should benefit from this, but travel is not as big an issue in the East Conference.

Clearly, the West Conference has a much bigger issue with travel than the East Conference. This allows for West Conference teams to have the biggest differential in tired games vs. tired games of their opponents. Although, they might want to trade that for the easier travel of the East Conference, it allows them to have the biggest advantage or disadvantage from travel. This advantage or disadvantage is likely seen in the regular season results. However, the significantly reduced travel of the East Conference might be the best situation of all for a team.

Saturday, July 19, 2008

Making Sense Of +/-

In a sabermetrics and hockey discussion of defence, the usual starting point is +/- ratings. +/- ratings give a player a plus when he is on the ice for an even strength or short-handed goal and a minus when he is on the ice for an even strength or short-handed goal. This statistic does not measure defence per se. It is an attempt to measure the overall quality of a player. A high scorer can have a good +/- rating without playing great defence because he is high scoring and a lower scorer can have one if his team allows fewer goals when he is on the ice than they score. It is one measure where good defence may come out, if a player appears much higher in the +/- ratings than he should be from offence alone.

The biggest problem with +/- ratings is comparing between different teams. A player on a good team will have a good +/- because his team regularly scores more goals than they allow (independent of the player involved) and a player on a bad team will have a bad +/- rating because his team regularly allows more goals than they score (independent of the player involved). In order to attempt to compare players on different teams, it is necessary to establish a baseline for a given team to compare individual player with.

The most successful method to do this (in my opinion) is the on and off ice +/- calculated on behind the net.

The theory behind this technique is to compare +/- ratings for players when they are on the ice with that of their teammates when they are off the ice. This is best done when ice time is normalized out of the problem. Hence, instead of reporting +/- ratings as counting stats (as is done by the NHL), they are reported as +/- ratings per 60 minutes of ice time.

As an example, let's look at Selke Trophy winner Pavel Datsyuk. Datsyuk plays for the Stanley Cup winning Detroit Red Wings and thus should have a good +/- because of his team. He is also a good scorer and a good defensive player. This should give him a good +/- after adjustment for his team as well. When Datsyuk was on the ice last season, Detroit scored 4.04 goals per sixty minutes and allowed 1.84. This makes him +2.20 goals per 60 minutes. When Datsyuk was not on the ice, Detroit's offence was much less spectacular scoring only 1.90 goals per 60 minutes, but their defence allowed only 1.75 goals. Thus when Datsyuk is off the ice, his team had a 0.15 +/- rating. This gives Datsyuk a net +2.05 on and off ice +/-. This is a very good number and is strong evidence that Pavel Datsyuk is one of the best players in the NHL.

Of course, these numbers are not perfect. All players on a team are not used in the same situation. Some players match up against the opposing team's best scorers and others against weaker players on the opposing team. Some players tend to play with better linemates than others. These factors will also affect +/- ratings.

In an attempt to find good defensive players statistically, +/- ratings are a start. This can be significantly improved by comparing them to a baseline for a given team (so that comparison between different teams is possible). Comparing a player's +/- when he is on the ice against his team's +/- when he is off the ice is a very good way to do this.

Friday, July 18, 2008

IIHF Takes Action?

The International Ice Hockey Federation (IIHF) is trying to weigh in on the questionable player transfers this summer. Since Alexander Radulov is under contract with the Nashville Predators of the NHL despite signing with Saavat Yulaev of the KHL he has been "suspended" by the IIHF. The IIHF claims Radulov is suspended from all international transfers and competitions, while they investigate the matter. The problem with this suspension is that there is no formal player transfer deal involving the IIHF so it's not clear that they can suspend him from any international player transfers. If Radulov plays in the KHL, they may be able to punish the Russian hockey program, but it is not clear how. The part of this suspension they can hold up is barring Radulov from any international competitions such as the World Championships or the Olympics. The problem there is until spring 2009, there is no international competition that Radulov is likely to be involved in (the World Championships occur then).

The IIHF is also investigating some of the NHL's questionable player transfers. This includes Jason Krog signing with the Vancouver Canucks and Tomas Mojzis signing with the Minnesota Wild as well as Fedor Fedorov who signed with the New Jersey Devils (and is under contract to the Moscow Dynamo of the KHL), Nikita Filatov who signed with the Columbus Blue Jackets who drafted him in 2008 and is alleged to be under contract with CSKA Moscow and Viktor Tikhonov who signed with the Phoenix Coyotes (who drafted him in 2008) and is under contract with Cherepovets Severstal.

Likely, all the IIHF can do is bar these players from international competition while they play in the league of their choosing. They can attempt to punish the league or country that allows them to play, but their power is limited. If either the NHL or KHL thumb their noses at the IIHF little can be done. It is unlikely that they would be barred from Olympic participation as they are the best nations in the sport and it would ruin the tournament.

The IIHF is a relatively powerless organization to oversee international hockey unless the major hockey powers cede power to them, which is not being done. They can attempt to put pressure on Radulov, Krog, Mojzis, Fedorov, Filatov and Tikhonov to return to the leagues they first committed to (if they find those contracts binding), but there is no guarantee that pressure will work. Their suspension of Radulov holds little threat. He could play in the KHL while suspended.

Here is TSN's story on this situation.

Thursday, July 17, 2008

LA Kings Have A Coach

It is a little bit beyond the midpoint of July. Free agent signing has been underway for almost three weeks. Most of the good ones are gone. The draft and the trades that accompany it are long over. Many team's rosters for next season are getting set. The Los Angeles Kings have finally got around to picking a new coach. That is something that they should have done about a month ago, but they are finally doing it now. It is something I have criticized them for. A well run team would have had the coach on board to provide input in the roster decisions that the Kings have already made.

The new Los Angeles Kings coach is Terry Murray. Murray is a veteran coach with 737 NHL games experience with the Washington Capitals, Philadelphia Flyers and Florida Panthers. He is an unspectacular choice who likely won't give LA any advantage in coaching most nights, but they could do worse. He is typical of the kind of coach you hire if you wait this long. He is an NHL veteran who is happy to get a head coaching job with any suitor. He has never been considered one of the better coaches in the NHL. He is basically your replacement level coach.

Los Angeles GM Dean Lombardi and Terry Murray already have a relationship. They both worked in the Philadelphia Flyers organization before coming to LA. Lombardi was a scout in the organization and Murray a scout and later an assistant coach. If Murray was Lombardi's first choice, there is no good reason he couldn't have hired him a month ago. It would have been better for the organization. If Murray is a last resort choice that Lombardi settled for because he was too slow to hire the coaches he wanted, it is already a bad situation.

Los Angeles has been slow to do anything this summer. They have not added any free agents. They traded away Lubomir Visnovsky and Mike Cammalleri for questionable return. They look like they could have a very poor season. One in which both Lombardi and Murray could get fired. They currently have the lowest payroll in the NHL ($29 million and change). Given the salary floor of $40.7 million, they have to add a significant amount of expense to the team. I do not see who is out there that will help them spend that money in any wise manner. Likely the team will be forced to overpay some mediocre free agents or trade for expensive castoffs from other teams in salary cap trouble. This is no way to build a competitive franchise.

The Los Angeles Kings finally have a coach. They waited a long time before selecting Terry Murray, a man they could have hired long ago. They also seem to be waiting a long time before signing free agents. Maybe if Los Angeles is hiring a coach now, they may get around to the free agent market in August. This is a poorly run team that should finish well back of the playoffs.

Here is TSN's story on the Los Angeles coach hiring.

Wednesday, July 16, 2008

Questionable Player Transfers Go Both Ways

One of the stories of the summer is the lack of an international player transfer deal. Some resolution appeared to be made when the NHL and KHL agreed to honor each other's contracts. This ran into problems when on the same day of the announcement, it was announced that Alexander Radulov, who is under contract with the Nashville predators of the NHL signed a contract with Saavat Yulaev of the KHL. The mainstream North American media (and much of the blogosphere) has been quick to paint the KHL as the bad guys (for example here), but it is not that simple.

The NHL has signed players who are under contract in the KHL as well. To the best of my knowledge, there have been two disputed signings: Jason Krog by the Vancouver Canucks who has signed with Severstal Cherepovets of the KHL and Tomas Mojzis by the Minnesota Wild who was signed by Sibir Novosibirsk of the KHL.

Jason Krog had a superstar season in the AHL where he led the league in scoring in both the regular season and the playoffs. He signed with Severstal Cherepovets when his season ended, but then signed with the Vancouver Canucks when he was offered a one-way NHL contract. Krog claims he had an out in his contract that would allow him to sign in the NHL by August 1st, but the Russians dispute this.

Tomas Mojzis played in the Russian League last year with Sibir Novosibirsk and was signed to play with them again this year when he signed with the Minnesota Wild. Most likely, he will play some or all of his upcoming season in the AHL.

So far, Russia signed the best disputed player who is already under contract, in Radulov, but the NHL has not been totally innocent. There is a fight for players between the NHL and KHL. Right now the NHL has most of the best players in the world, but not all. The KHL will likely gain an increasing number of the top players in the world. In this battle, the NHL is not the innocent victim. Both sides have been involved in questionable signings.

Tuesday, July 15, 2008

The Islanders Are Poorly Run Too

A few days ago I wrote a post entitled a poorly run team in which I called the Los Angeles Kings a poorly run team in part because the have still not yet hired a coach for next season. Any well run team would have put their coaching and management in place well before the draft in June, so that this management can discuss their options and make their best attempt to improve themselves in the off season. This was a follow-up post to a sign of a poorly run team, where I criticized the Atlanta Thrashers, Tampa Bay Lightning and Toronto Maple Leafs along with the Kings for their lack of a clear coaching and management team a few days before the draft. Of course this is not the only way a team can be poorly run. It is possible to install Beavis and Butthead as you coach and general manager well before the draft and you would still have a poorly run team.

In the comments of the poorly run team thread faux rumors commented that you can add the New York Islanders to the list of poorly run teams. Of course he is right. To show how poorly run the New York Islanders are, one must only read this post from a couple years ago about the mess created when Garth Snow (the backup goalie) became the team's GM.

It seems the Islanders were eager to prove Faux Rumors right. They waited until two weeks into July before deciding to fire coach Ted Nolan. Nolan was one of the few things that worked well in the Islanders organization. He is a good coach who I would have nominated for the coach of the year this year and last year also. In fact for a while in the 2006/07 season, I had Ted Nolan as the Adams Trophy favorite.

Why was Ted Nolan fired? Largely because he sees that Islanders owner Charles Wang (through his puppet GM Garth Snow) is running the team into the ground and he spoke out about it instead of staying quiet. On a poorly run team (as in George W Bush's administration) loyalty is more important than competence. If the people who own the team are making stupid moves, telling them the moves are stupid will lose you your job. Making those stupid moves keeps you employed. This is exactly how you fail. A good team doesn't have "yes men", they have good hockey men. Ted Nolan was the last good hockey man on Long Island.

The Islanders find themselves opening their rookie camp with no head coach and with the assistant coaches (who were largely brought in by Nolan) in limbo. The Islanders definitely belong on any complete list of poorly run teams.

Here is TSN's story on the Ted Nolan firing.

Monday, July 14, 2008

Sabermetrics And Defence

In the summertime when hockey news starts to slow down, I like to write about hockey sabermetrics issues. I have a reasonable archive of sabermetrics posts.

This summer, I thought I would try to address the sabermetric problems of rating a player's defensive ability. This is a tough problem and one that is not fully solved, but there are several techniques to try to identify the best defensive players. I will try to address some of them with their pros and cons.

By its nature, defence is hard to rate. You cannot easily assess how many goals a given player prevented (the same way you can assess how many a player scored). Defence is a team related activity. Even if you do a great job of taking your man out of the play, another player on the ice may score. It is hard to separate individual contributions from team results. As a fan watching a game, it is easy to see spectacular plays or significant mistakes and miss the play of a steady defensive player who almost never allows an offensive opportunity to develop.

Defence is very important to winning hockey games, but assessing it statistically can be difficult. I hope to look at some of the problems in this assessment and some of the methods that can be used to try to gage a player's defensive contribution.

Sunday, July 13, 2008

Columbus On The Road To Mediocrity

The Columbus Blue Jackets have been a bad team for their existence. They have never made the playoffs. A lot of the blame for that goes to their first GM Doug MacLean, although Scott Howson will soon be earning some of that blame for himself.

This summer, the Columbus Blue Jackets have made significant changes to their roster. The acquired RJ Umberger from the Philadelphia Flyers (along with a fourth rounder) for a first and third round pick. Is Columbus the kind of team that should be trading away their first round draft picks in order to bring in players like Umberger who are clearly not stars and would not be on the top line in many NHL cities? Not if the want to make a run at the Stanley Cup in the future. However, if they are will to take a longterm loss in order to try to make playoffs for a first time it can make some sense. Columbus has given up on any goal of being a great team and would be happy to finish 16th and in the playoffs.

Umberger was not the only trade that shows this desperation. 2005 first round draft pick Gilbert Brule was shipped to the Edmonton Oilers for Raffi Torres. Brule possesses the potential that he could be an important part of a young core (though he may never realize it) and Torres is a proven NHL player who lacks that upside. This is another move which shows the goal is to make playoffs now even if it costs the chance of being great later on and for a longer period of time.

Columbus also traded their first and second round picks from 2003 in Nikolai Zherdev and Dan Fritsche to the New York Rangers for Fedor Tyutin and Christian Backman. This is yet another example of trading the younger players with higher upsides away to bring in safer NHL players who are likely to never be dominant.

All three trades show that Columbus is will to trade pieces of their youth and future for prove NHL players without upsides. It gives them more NHL players right now and helps them out in their goal to make playoffs. They are more likely to in the race for 16th place and a final playoff spot, but it moves them further away from what should be their goal of winning the Stanley Cup someday.

A lower budget team like Columbus has had to sign some free agents to ensure they make the salary floor. Since, in general free agency is no way to turn a team around; these signings won't turn Columbus around. Sure they added Kristian Huselius, Mike Commodore and Mike Peca and that gives them more NHL talented bodies in their quest for a playoff spot, but it won't help them if their goal is Stanley Cup contention.

It is easy for a GM of a weak team to turn his goal toward making playoffs instead of eventual Stanley Cup contention. The goal will take less time to obtain and is a much easier one. The problem is the two goals can contradict one another. To make playoffs now it makes sense to trade young players with bigger upsides for established NHL players who lack those upsides. Columbus has done that. They traded out a first round pick and two former first round picks to get an older team this summer. While it might put them closer to a playoff berth (and likely first round loss), it moves them further from any hopes of actually winning the cup. That is a shame, because Rick Nash and Pascal Leclaire might have been two important pieces of a goodyocore that could lead them to success if they could find a few more pieces to join it. Some of those potential pieces have now been traded for players who won't offer that potential.

The Doug MacLean Columbus Blue Jackets failed in part because too much of their roster was used on older players who were on the downsides of their careers (Sergei Fedorov, Adam Foote, Luke Richardson etc.). This impeded the progress of their young players. It looks like the Scott Howson Columbus Blue Jackets have decided to move out those young players for an older group of guys who lack those upsides. In either case, a successful Columbus blue Jacket team looks unlikely.

Saturday, July 12, 2008

Jay Feaster Out As Tampa GM

Ever since Oren Koules and Len Barrie took over as Tampa Bay ownership it has been clear that they want to do things their way. Almost all ties to their past are being broken. Head coach John Tortorella was fired and replaced by Koules friend Barry Melrose. Numerous player personnel moves have been made. All of this has happened without Jay Feaster, the Tampa Bay GM at the time being involved.

Former scout Brian Lawton was brought in as the director of hockey operations and is the presumptive new GM. It has been Lawton, Koules and Barrie announcing all the changes in Tampa Bay, with Feaster no longer to be seen.

Jay Feaster has been forced into resignation of his position as Tampa Bay GM. The remaining three years on his contract will be honored financially. Feaster was the general manager for the 2004 Stanley Cup championship and although the Lightning fell on hard times last year, had shown himself to be a good hockey man. It is unclear that Lawton (or Koules ... or Barrie) has the general management ability that Feaster did.

History shows us that when ownership is heavily involved in the day-to-day running of a franchise it usually ends badly. History has shown us that organizations who throw away useful contributors like Jay Feaster (or on the ice Dan Boyle) usually wind up in disaster.

The Tampa Bay Lightning will be interesting to watch this season. They have a new ownership that is willing to do brash untraditional things. I am skeptical as to whether that will lead to success on the ice. I think Jay Feaster is likely a better option as general manager than the people currently in charge, but this Tampa Bay ownership group doesn't care what I (or anyone else) thinks.

Friday, July 11, 2008

Transfer Agreement Progress?

The NHL is without a transfer agreement to govern players who jump between the various international hockey leagues. Russia opted out of the IIHF transfer agreement in 2005 and the rest of Europe joined them this season.

The concerned parties met in Zurich, Switzerland yesterday and came to a partial agreement. The various leagues agreed to honor each other's contracts, with penalty of non-participation in the Olympics if this is violated (though this is likely an empty threat). A further meeting is scheduled for September when it is hoped a full transfer agreement can be hammered out where the amount of financial compensation owed to a league when a player from that league jumps to a new league can be negotiated. The main issue is that European leagues feel the $200,000 US payment they currently receive is not sufficient.

This is substantial progress. There have been a few cases of Russian players under contract in the NHL jumping to Russia (such as Roman Voloshenko and Canadian Fred Brathwaite), There have even been isolated cases of Russian players jumping to the NHL (such as Alexei Semenov). This agreement would help reduce this instability.

However, approximately the same time this agreement was announced, it was also announced that Alexander Radulov has signed with Saavat Yulaev of the KHL. Radulov is about to enter the third and final year of an entry level contract with the Nashville Predators. According to the agreement reached, his signing should not be allowed. It is quite likely that his contract was negotiated by Saavat Yulaev without their knowledge of the agreement to respect contracts, so the Russia ice hockey federation was likely not bargaining in bad faith.

Radulov will make significantly more money playing in the KHL than he would on an entry level deal in the NHL. This is one problem of the NHL's entry level deals. It might keep some players from joining the league if they can get higher paying contracts in other leagues.

The loss of Radulov is a blow to the Nashville Predators. He was their third highest scorer last season, with 58 points and expected to increase those totals in the future.

We will immediately see a test of the international agreement. Will the KHL honor Radulov's NHL and send him back to the NHL? Would Nashville want him, if he clearly does not want to be there? Is yesterday's agreement already dead? Will the threat of no Olympic participation actually be followed through with?

The war over players between the NHL and the KHL is underway. It is going to get ugly. Right now the NHL controls most of the best players in the world, but the KHL is slowly trying to chip away at that. Alexander Radulov is one of the first chips.

Thursday, July 10, 2008

Leafs CBA Mess

One of my complaints about this CBA is that it is needlessly complex. It removes understanding of many of the moves in the game from the fan due to its complexity. Here is a case in point.

The Toronto Maple Leafs have been attempting to sign defenceman Jonas Frogren from Farjestads BK Karlstad of the Swedish Elite League. He is a stay at home defenceman who played very well in the World Hockey Championships. By the Leafs understanding, Frogren, who will be 28 by next season, could be signed to a standard NHL contract. In general, players 28 and older do not require entry level contracts when they join the NHL. They negotiated and signed him to a contract. Frogren was under contract to his Swedish team, but he could buyout his contract (basically paying back a signing bonus) if he chose to leave. It was negotiated that Frogren would pay back the bonus himself (since NHL teams are forbidden by Gary Bettman to pay transfer fees to European teams with the current lack of a transfer agreement). The Leafs would then pay Frogren his planned salary plus the buyout as his 2008/09 NHL salary.

The snag is that Frogren was drafted in 1998 by the Calgary Flames, but never given a contract offer. Under the pre-lockout CBA, such a player was classified as "defected" by the NHL if he later came to the NHL with a team other than his drafting team (which no longer held his rights). This classification is a poor name because it doesn't actually have anything to do with a player defecting. It was agreed, in negotiating the expired IIHF player transfer agreement that it would be best to treat such cases the same way defecting players are treated. This language was left in the current CBA, probably without considering consequences. Defecting players, regardless of age, were to be required to sign entry level contracts.

Thus, the NHL rejected Frogren's contract because he is a "defecting" player. He would be eligible to sign a standard contract except that he had been drafted in 1998 (which seems like a largely irrelevant fact). The problem with his signing an entry level deal is that it may not cover the buyout money that has already been spent.

As a result, we get a legal mess. The contract of a player is rejected because of a remnant of an expired agreement that is in the CBA. It has Frogren treated differently than most other people in his position and is thus unfair to him. I am pretty certain Frogren will sign with Toronto, but I am not sure how this will be worked out. It has potential to force so re-working of the CBA and how European players are treated.

Here is TSN's story on the Frogren attempted signing.

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