With Christmas just passing into the rear view mirror,, and the accompanying three day hiatus from active NHL action coming to a close, it seems the perfect time to take a slightly festive and irreverent look at a fairly basic element of the game of hockey -- shooting. With the metaphorical assistance of A Christmas Story, we'll examine the process of putting the biscuit in the basket from a slightly different perspective.
When A Shot Is Not A Shot
Assume Santa just brought you your very own Red Ryder carbine-action 200 shot range model air rifle--complete with a compass in the stock -- and you want to take it out for a test spin. You load it up, set up your target (dodging icicles from the garage along the way), and fire off ten shots. Out of those, you miss the target completely nine times, but manage a bulls-eye with the one shot that found the target. So, what is your percentage of bulls-eyes? Most of us, I think, would agree on .100, or 10%, right? Well, not if you're in the NHL, where you would enjoy a bulls-eye percentage of 1.000 (100%). Wait . . . really??
Certainly, it's true that hockey does not use shooting percentage to anything approaching the extent to which it is used in basketball, or batting average in baseball, but ultimately it is still a mathematical representation of the ultimate object of the game -- scoring. So, it seems curious that the NHL does not truly calculate the shooting percentage based upon shots attempted -- but rather upon a subset of that number -- the shots deemed to be "on goal." To continue the Ralphie analogy, the NHL only counts the shots that hit the target, then determines what percentage of those hit the bulls-eye, i.e. result in a goal.
It's truly a strange construct. Consider that there are precisely four things that can happen when a hockey player attempts a shot: the puck can miss the net entirely, it can be blocked by a player before reaching the goal; it can be on goal, but saved by the net minder, or it can go in the net for a goal. The NHL already tracks missed shots and blocked shots, so it's not like the calculation is difficult. Curious. Let's look at the numbers and see what they reveal.
By The Numbers
The impetus for this exercise was an impression I had that the Blue Jackets were not terribly proficient shooters - -as a team. It seemed that they had an inordinate number of shots miss the net or blocked by the opposition. It turns out that I was only half right.
The following table charts each club's efforts for the first 30 games or so this season (range from 27 games to 32 games), showing the percentages of shots attempted that scored, were saved, blocked or missed -- sorted by scoring percentage:
Of course, the most obvious inference from the numbers is that goals are really, really hard to come by. The best team in the league fails to convert just about 94% of the time, while the worst misses the mark 26.5% of the time. Another easy observation is that there is really not a lot of divergence in terms of this "true" shooting percentage -- a total gap of just 2.5% from 1st to 30th.
While the shooting percentage itself tracks overall success on the ice reasonably well. with St. Louis, Anaheim, Chicago, Pittsburgh all near the top, and Buffalo and Florida at or near the bottom , the relationship is not perfect. Obviously, we are looking at only one side of the equation -- shooting -- and the impact of defense and goaltending do not come into play in this analysis. However, even within these numbers, some more interesting distinctions can be drawn.
While putting the puck in the net is the ultimate goal, another consideration is how frequently the puck is put on goal. Even saves can create opportunities via rebounds, so perhaps the total SOG tracks success a bit better? Not really. Using this number (Goals + Saves), Detroit is the NHL leader, putting the puck on net 58.91% of the time. The Red Wings are followed closely by Nashville, Anaheim, Phoenix and Vancouver, Surprisingly, Florida ranks 8th using this metric, while St. Louis slips to 19th. Los Angeles, Chicago, Boston and Dallas all fall in the bottom six here, suggesting that perhaps putting the puck on goal -- in and of itself -- is not the offensive advantage one might think.
In terms of missing the target altogether, the Colorado Avalanche prove the best here, missing only 19.32% of the time. In second? The Blue Jackets, at 19.38%. Thus, my hypothesis that Columbus suffered from a woeful shooting eye was drastically wrong, at least in relative terms. However, this fact is not necessarily a consolation, as the Sabres hold the third place slot here, missing only 19.69% of their shots. The Red Wings are the fourth and final club to miss fewer than 20% of their shots. At the other end of the spectrum are the Maple Leafs-missing 27.09% of their shots -- with the Islanders (26.87%), Kings (26.71%) and Wild (26.63%) also in danger of metaphorically putting their eyes out.
Briefly looking at blocked shots, Edmonton leads the NHL here, having only 18.98% of its shot attempts blocked. Minnesota, Nashville and Vancouver follow, all with fewer than 20% of their attempted shots blocked. On the other end of the spectrum, the Boston Bruins have had 27.56% of their shots blocked, and Columbus is right there, with 27.36% blocked. Carolina, Chicago, Buffalo and Dallas all have more than 26% of their shots blocked.
So far, looking at the percentages has not proven to be entirely reliable in demonstrating offensive success overall. St. Louis has certainly been efficient in scoring goals, but with the narrow gaps in the true shooting percentages, those numbers seem likely to narrow as time progresses. Teams with offensive success inexplicably have high percentages of shots blocked or missed, while teams struggling in the offensive zone show up remarkably well in some of these metrics. So, what is missing? One word . . . volume.
Try, Try . . . and Try Again
When you have relatively low percentage margins of difference, the only way to consistently make those margins pay off in real terms is to increase the volume. It's basically the same concept that low-margin businesses use to succeed. Here's how the clubs rank in shots attempted per game:
|Team||Shots Attempted Per Game|
This brings us closer to an understanding of how the numbers combine to explain the results we see on the ice and in the standings. As we saw above, neither shooting percentage alone -- nor shots on goal -- correspond well with the observed success and failure of the NHL clubs so far this year. However, the volume component explains more. First, there is a significant divergence between the haves and the have-nots when it comes to attempted shots. San Jose tries 47% more shots per game than Buffalo . Applying an average 5% shooting percentage to their respective numbers results in a 1.1 goal per game differential, which is significant. Of course, Buffalo has a worse shooting percentage than San Jose, so the effect is magnified in reality.
Again, attempted shot volume -- by itself -- is not a perfect predictor of offensive success, but it is a critical component, and helps in identifying areas where teams might be struggling. At one end you have clubs like Chicago, which ranks 2nd in attempted shots and fourth in "true" shooting percentage, and leads the league (in this sample) in Goals Per Game, despite ranking only 25th in Shots on Goal. St. Louis is 2nd in Goals Per Game, leveraging its top slot in shooting percentage, while only raking 15th in attempts and 19th in percentage of shots on goal. That might suggest a club that is more vulnerable over the long haul, should the sniper percentage decline.
At the other extreme, Buffalo ranks last in both attempts and shooting percentage, pretty much guaranteeing its last place rank in goals per game. However, they rank 12th in the percentage of shots on goal. Philadelphia has a 29th place ranking in both shooting percentage and goals per game, but has used defense and goaltending to stay in the playoff hunt. Conversely, Ottawa ranks 3rd in attempts, 18tht in shooting percentage and 10th in goals per game, yet is two games below .500, suggesting that its issues lie at the other end of the ice.
For the Blue Jackets, the numbers also seem to adequately explain much of the observed performance. The Blue Jackets rank 15th in both shooting percentage and percentage of shots on goal, but a paltry 26th in attempted shots per game. That translates (again, for this statistical sample) to a 22nd place rank in goals per game. The lesson: shoot the puck!
Wrapping It All Up
As we come in from the cold, wipe off the old air rifle and assess the performance, a few things seem clear. First, shooting percentage, whether calculated with reference to shots on goal (as the NHL does) or in comparison to total shots attempted, is a relatively small and unreliable part of the entire picture. The spread among the 30 teams is perilously narrow, which makes the ultimate viability of the statistic questionable.
What does seem equally clear, however, is that reliance on shots on goal -- either to determine shooting percentage, or as an independent predictor of offensive success -- is misplaced. First, it is simply mathematically dishonest to only count shots on goal in determining shooting percentage. Secondly, we've seen that the percentage of shots on goal does not correlate well to success.
It seems that only when we factor in total attempted shots do we get the complete picture. Sure, the more shots attempted, the more shots will be on goal. However, the numbers show that success tracks the total attempted shots better than it does the on goal shots. For the most part, if you attempt a shot, you're in the offensive zone. If you're in the offensive zone, you are exerting pressure, and your defense and goal-tender are not being challenged. Those are good things, and ultimately tend to lead to success.
I've perused tons of box scores, and have seen plenty of games where the team trailing in shots on goal prevails. When I look at total attempted shots, that number drops significantly. It's simple really -- shots consume time and create opportunities, whether they bounce off the glass, the goaltender or another player.
So, while shooting percentage will never have the significance in hockey that it does in basketball -- nor the weight of batting average in baseball -- it does lead us to look at shots attempted, not just shots on goal. In the long run, that's a much better predictor of offensive success.
In a future article, I'll look at how this translates in individual performances, but for the meantime, check out those missed shot and blocked shot categories. They'll give you the complete picture. One thing is certain -- the real shooting percentages would have Red Ryder shaking his head in dismay.