NHL Coaching: By the Numbers
Coaching has been a recurring topic of conversation on The NHO Show, and for good reason. It’s often an ignored aspect when praising a successful team, but always the first position to receive criticism when a franchise is struggling. It remains one of the most paradoxical career choices an individual can make, with extremely low job security but never-ending opportunities. Joel Quenneville is the longest-tenured coach in the league, spending the last nine seasons with the Chicago Blackhawks. In second is Alain Vigneault and Jon Cooper at four years, followed by Paul Maurice at just under three seasons. That may seem like a short time, but it’s not surprising when the average tenure of current NHL head coaches is 2.5 years. In fact, there are 11 NHL coaches that started with their team in 2017 meaning over 1/3 of the league have hired a new coach since this time last season. Talk about added stress in the workplace.
More oddities appear with further analysis. Consider that Bruce Boudreau, the winningest coach of all time with wins in 66% of 763 NHL games, finds himself on his third team in six years. Boudreau’s lack of success translating this winning percentage into the playoffs is what keeps him on the move, but one would think he would have been given a longer leash in most cases. Once a head coach is fired, it’s common that he will be replaced by one previous NHL experience, like Ken Hitchcock in Dallas this season. This trend is slowly changing with six rookie bench bosses this season, although it is still too early to evaluate coaches like Phil Housley, Rick Tocchet and Doug Weight. However, with current trends, it would not be surprising if half of these rookies are out of a job this time next season.
The constant recycling of NHL coaches indicates that in many circumstances, failure is not because of an incompetent coach, but rather the result of a stale relationship between coach and team. Each coach has a particular style which he has leaned on to get to the NHL level. Long-time coaches Hitchcock and Julien are well known for their defensive structure, whereas Ruff and Laviolette are known to push the pace offensively. There is no “right way” to coach, as each style has proven effective in winning the Stanley Cup. However, it is essential that the coaching style compliments the personnel on the team and vice versa. The single most important decision a general manager can make is to select a coach that creates this symbiotic relationship. This has proven to be easier said than done, with all but two teams hiring new head coaches since the beginning of the 2014 season.
Jack Adams Means Jack
Another anomaly of NHL head coaching is that some of the best at their craft have never been formally recognized in the form of a Jack Adams trophy. Like the Norris, the Jack Adams has been awarded improperly several times because of face-value metrics. While this isn’t true in all cases, 10 of the past 12 winners have been fired since winning, and only half of them are still NHL head coaches. It has become a trophy awarded either to the coach that captured the President Trophy or defied expectations to sneak into the playoffs. Therein lies the problem. Any accomplishment that is rewarded based solely on the criteria of prior expectations is inherently flawed. Meanwhile, widely-accepted elite coaches like Joel Quenneville and Mike Babcock find their trophy cases missing this piece of hardware. So, how does one properly evaluate and select a head coach? I’m glad you asked.
Shot Attempt Percentage
While there are a number of metrics one can use to determine the effectiveness of a head coach’s system, we are going to focus on one in particular – shot attempt percentage or SAT%. SAT% is simply a ratio of 5-on-5 shot attempts for versus shot attempts against and is widely accepted as the best indicator of what leads to a successful team. This is based on the notion that puck possession wins games, and because a head coach’s primary role is to win games, he will want to implement a system that maximizes puck possession. While there’s no guarantee that the best possession team will finish first in the standings or win the cup, historically there is a strong correlation with the top SAT% teams and making the playoffs. Of course, there is a myriad of ways to measure the effectiveness of a head coach, but SAT% was chosen for its simplicity and direct relation to a coach’s systematic approach. Special teams were ignored because although a head coach has input on these systems, they are largely the responsibility of his assistants.
The table shows each coach’s SAT% over his current tenure, and his team’s previous SAT% under the old regime. Obviously, not every team is created equal which gives an inherent advantage to some bench bosses, so it’s more important to look at trends rather than the numbers alone. A quick analysis of this chart can be very revealing:
- 71% of teams that finished in the top 16 have made the playoffs over the last three seasons.
- Only two teams have made the playoffs each season of those that finish in the bottom 10 in SAT%.
- Teams with recent coaching changes that are trending in the right direction include Calgary, Edmonton, Toronto and Columbus
- Those trending in the wrong direction, and perhaps should consider a change include the New York Rangers, Colorado, and New Jersey
- This chart seems to justify the firings of Jack Capuano, Willie Desjardins, and Dave Tippett, though the jury is still out on their replacements
- Not surprisingly, experienced coaches like Darryl Sutter, Claude Julien, Lindy Ruff and Bruce Boudreau seemed to have been fired unjustly.
- Though currently high in the standings, teams like Winnipeg and New Jersey will want to control the play more if they want continued success
- Similarly, playoff hopefuls like Washington, Minnesota, and Ottawa are playing with fire if they want to advance to the second season
The most surprising part of this chart is that Bill Peters’ Carolina Hurricanes have finished in the top 10 (and currently lead the league) in SAT% for the last three seasons but have yet to make the playoffs. Similarly, Alain Vigneault’s Rangers have been in the bottom half three seasons in a row but have been a playoff team in each of those seasons. Los Angeles is another outlier as they have led the league in SAT% each of the last three seasons under Darryl Sutter but missed the playoffs twice in that span. If Sutter and Peters are elite at creating puck possession teams, why hasn’t that translated into more wins? There’s something important we aren’t considering that goes a long way to explain this phenomenon: PDO.
Factoring in PDO
PDO is simply a team’s save percentage plus their shooting percentage, and is the best way to quantify ‘puck luck’. Since the sum of all saves and goals scored league-wide equals the league’s shot totals, the PDO for the entire league is 100%. The more puck luck a team has, the higher the number will be. Though high-end goaltenders and elite snipers can skew this number in their team’s favor in a small sample size, it has been proven that over long periods team shot and save percentage are luck-based metrics. Let’s re-evaluate our coaches using this as an added metric.
This chart almost perfectly explains the inconsistencies in the SAT% chart. Here are a few things that stand out in this sample size:
- 82% of teams that finished with a SAT% + PDO above 150 made the playoffs
- Only two teams in three seasons have made the playoffs with a PDO under 100 and SAT% below 50
- 83% of teams that finished in the top 10 in PDO have made the playoffs
- This season there are five teams with a PDO currently over 102. Only three teams in the last three years have finished the season above that mark so we can expect regression towards the mean.
- It appears that a poor SAT% can be overcome with a strong PDO, but rarely does that relationship work in the opposite direction.
Given these statistics, there are conclusions to be drawn from each team’s place and the standings and likely trajectory:
- These numbers do not bold well for the Rangers making the playoffs, and the Senators could find themselves in trouble if their PDO slips below 100
- Teams with high PDOs usually have good goaltending and elite shooters. Tampa Bay is benefiting from both of these this season despite being on the wrong side of SAT%
- Connor Hellebuyck and Winnipeg’s potent offense are keeping the Jets afloat, camouflaging their atrocious SAT%. When they regress towards the mean in PDO, Paul Maurice’s job could be in trouble.
- Hard to believe Edmonton’s struggles lasting much longer with a PDO of just over 98 but a strong SAT% over 55.
- Ben Bishop can provide the Stars can get some average goaltending they will start their ascent in the standings.
- Julien has Montreal playing a strong possession game but they need to start converting on their chances more consistently to see improvement
- It should come as a surprise to no one that the Devils current success might be short-lived, boasting an unsustainable PDO of over 103 with a SAT% just over 45.
- Watch out for Pittsburgh. League-worst PDO but still near the top of their division.
To a point, a coach can control his PDO by instituting a system that creates high danger scoring chances and limits the opposition in generating quality chances of their own. But ultimately this comes down to personnel. It’s no surprise that teams with elite goaltending like Washington and New York consistently find themselves in the top tier. This is evidence of how a goaltender can save or ruin a coaches career, as Henrik Lundqvist has been keeping the Rangers PDO above 100 despite a consistently poor SAT%. On the flip side, Bill Peters is hoping Scott Darling can change his luck before he finds himself out of a job. As mentioned in last weeks podcast, the Hurricanes could also use a more lethal offensive threat.
This is a fairly rudimentary analysis of coaching, and it’s important to remember several integral factors to being a successful head coach are being ignored, such as special teams (which has kept the Penguins afloat early on) player deployment and playoff performance. However, with strong linear relationships between 5-on-5 SAT% and PDO to winning, these are trends that should not be ignored. The data confirms that Paul Maurice and Alain Vigneault’s current positions should be on life support. Time will tell if Bill Peters will suffer the same fate as Darryl Sutter, who appear to be the two most undervalued head coaches currently in the business. It would be shrewd for a team like Colorado or New Jersey, both of whom are consistently in the basement for SAT%, to jump on the opportunity to hire either of these two before they are gone. Something tells me this isn’t the end of the NHO’s diagnosis of coaching.