All Shots are not Created Equal - New OZ Shooting Areas

In the hockey analytics world, we're all familiar with the offensive zone's home plate shooting area. An area starting from the edge of the crease, reaching both faceoff dots, and ending and the tip of their circles. It's a known fact that shooting from this area grants players the best probability to score a goal. Furthermore, there are many variations for the high-danger area within the home plate known as the slot. The most common is illustrated in the following image.

These are the common shooting areas that analysts use to categorize shots into different danger levels: Slot shot (A), Outer-Slot/Home plate shots (B), and anywhere else below the goal line (C). These tiers give us a good understanding of shooting and goal tendencies throughout the NHL based on shot locations that give the opposing goaltender the least amount of time to react as well as take into consideration the total net surface area visible by the shooter that isn't obstructed by the goaltender.

But what if we got even more precise?

I began working on a new project that aims to track and analyze passes in all three different zones. Within the various variables that I take into consideration to quantify each pass' quality, I wanted to create a variable that calculates the potential goal probability from a pass from player X to player Y. Without going into the details of player Y's shooting tendencies, I can get a good idea of the danger of his potential shot by getting the league's average goal percentage (Goals scored / Total shots) at the location of the pass reception. For example, it's easy to say that a shot from location A in the image below has a higher goal probability than a shot from location B, therefore a pass to location A would have a higher quality than a pass to location B.

This got me thinking that there should be a way of calculating the danger of a shot that comes from outside of the previously mentioned areas. The current slot and home plate shooting guide is a great starting point as 75.5% of offensive zone goals since 2013 have been scored from one of these two areas, but it disregards the 24.5% of OZ goals that are scored outside of their limits. That's why I decided to tackle the project of creating new zones and altering existing ones to take into consideration 100% of offensive zone shots.

To do so, I couldn't just draw lines to delimit new zones in a way that aesthetically made sense. At their origins, the home plate and slot areas were creating by examining an enormous quantity of shot locations that led to a goal. By computing all of these coordinates into a heatmap that visualizes locations with the most event occurrences, these two zones draw themselves: 

We can clearly see the diamond-like shape of the slot area as well as faint limits of the home plate. In that single image, 64,515 goals (Every OZ goal since 2013) were used to create the heatmap. By quickly looking at the result, it's safe to confirm that roughly 75% of OZ goals are indeed scored within those couple areas. Also, without getting technical with the exact value of goal probability from each area, by generating a heatmap of every single OZ shot (Goal or not), we can see that other areas begin to appear mainly at the point, but most importantly, away from the slot:

This 955,100 shots (Every OZ shot since 2013) heatmap allows us to see that from other areas, the goal probability is different than from the slot. If the probability would've been equal everywhere in the zone, the two heatmaps would be identical.

Going back to the goal heatmap, it is difficult to identify limits of different areas that could be created. This is because of the disproportionate number of goals scored from the slot compared to elsewhere in the zone. In order to view the natural limits of the new areas that I want to create, I would have to isolate the coordinates of goals scored outside of the slot and home plate to generate new heatmaps to analyze.

Here are the new zones that I came up with:

Oh wow, that's a lot of colors. Let me break it down:

 #1 - Low Slot

The sum of the first two areas are identical to the slot area that was mentioned earlier in this article. The reason I decided to divide it into two separate areas is because within the slot, you can obviously see two different areas on their own. From looking at the goal heatmap above, we can see an abundance of shots around the crease then a gradual fade in number of occurrences forming the spike of the slot.

Much like every other area, the main shot type are wrist shots that constitute 42.12% of shots and 48.38% of goals from this area. From the OZ, 17.50% of shots are taken from the low slot and, for these shots taken from that area, 15.12% of them were goals.

*63% of all players shoot left-handed and 37% are right-handed

Considering this information, there isn't a preferred shooting side for this area as 63.88% of shots and 63.81% of goals are from left-shooting players leaving 36.12% of shots and 36.19% of goals being from right-shooting players.

 #2 - High Slot

Here we have the second portion of the slot. In this portion of the slot, you won't see any of the gritty goals that are scored in the low slot. As previously explained, I created this new area due to the fact that players' shooting tendencies within the high slot differ greatly than from the low slot.

4.96% of all OZ shots are taken within the high slot (Much different than the low slot's whopping 17.50%). A player's scoring probability from this area is 12.31%. 

The most common shot type within this area is yet again wrist shots with 42.18% of all shots and 52.25% of all of its goals. Yet again, there isn't a difference from handedness with 62.84% of shots and 63.22% of goals coming from left-shooting players and 37.16% of shots and 36.78% of goals from right-shooting players.

 #3 - Outer Slot

The outer slot is the remaining area from the original home plate design, the last of the high danger areas.

This is the area where the most shots come from. In fact, 23.91% of OZ shots are taken from this area and 7.72% of these shots being goals scored.

The most common shot type in the outer slot is (you probably guessed it) wrist shots which constitute 58.09% of shots and 55.49% of goals from this area. Yet again being located in the middle of the ice, there isn't much of a handedness difference with 61.08% of shots and 60.54% of goals coming from left-shooting players and 38.92% of shots and 39.46% of goals from right-shooting players. Right-handed players seem to have slightly more success from this area, but the difference isn't great enough to write a whole research paper about..!

 #4 - West Point

The West point is one of the three point areas where defensemen typically shoot from once their team is set up in the offensive zone. As seen on the shot heatmap, three distinct shooting areas were formed, each with their own goal probabilities, hence the reason why I created three separate point areas.

10.09% of OZ shots come the West point with a goal probability of 1.90% (Much less effective that the low slot's 15.12%, obviously).

This is the first zone that differs in the most common shot type for goals. Most shot attempts from this area are still wrist shots (48.43%), however, the most common shot type for goals scored is slapshots with 44.78% of the area's goals. We also see a difference with the handedness of players shooting from this are that can be explained by the fact that most left-side defensemen shoot from their left. 79.20% of shots and 68.72% of goals from this area come from left-shooting players and the remaining 20.80% of shots and 31.28% of goals from right-shooting players.

 #5 - Center Point

The second of the point areas is called the center point because, well, it's in the center of the ice. Players shooting from this area tend to have more success than shooting from either side of it since the puck doesn't have to travel as far coming from the center point and because the angle of the shot forces the opposing goaltender to reveal more of his net by standing in the middle of the crease.

From the OZ, 13.97% of shots come from the center point and 3.56% of them being goals scored (Nearly twice as effective as West point shots with 1.90%).

47.89% of shots from this are are wrist shots which is also the most common shot type for goals with 41.85%. Although being an area in the middle of the ice, right-handed players tend to take more shots from this area with 41.48% of shots and 43.04% of goals coming from right-shooting players compared to left-shooting players' 58.52% of shots and 56.96% of goals.

 #6 - East Point

The final point area is called the East point.

9.89% of OZ shots come from this area, with a goal probability of 1.92%, roughly the same as the West point.

From this area, 46.22% of shots are wrist shots but the most common shot type for goals are slapshots with 42.57%. Contrary to the West point, right-handed players shoot more from this area, like much more. For the West point, we saw 79.20% of shots coming from left-handed players (+16.20% from the 63% of all players being left-shooters), however for the East point, 66.69% of shots come from right-shooting players (+26.69% of the 37% of players being right-handed) meaning that 33.31% of shots from this area are from left-shooting players. This difference is even bigger for goals scored: for the West point, 68.72% of goals were scored by left-handed players (+5.72%), in the East point, 57.60% of goals are scored by right-handed players (+20.60%). Either right-shooting defensemen adore shooting from the East point or left-handed players fear ever coming close to it because the difference between the two zones are drastic.

 #7 - West Wing

The West wing area is located deep in the OZ on the left of the faceoff dot. Shots from this area are not very dangerous since the angle of the shot puts the odds in the opposing team's goaltender since he can easily block off and limit the puck's path from going into the net. A good portion of the shots that originate from this are shots that aren't necessarily supposed to go into the net, but rather allow a player located in the low slot to get a rebound.

6.19% of OZ shots come from the West wing with a goal probability of 2.43%.

The most common type of shot from this area are by far wrist shots with 65.49% of shots and 50.06% of goals scored. This area sees a lot more shots from left-handed players (71.74%), however, these players register less goals (54.72%) compared to our benchmark of 63% of players being left-handed. This means that only 28.26% of shots come from right-handed players, yet 45.28% of goals are scored by them. Talk about efficiency.

 #8 - East Wing

Now onto the East wing, West wing's twin brother.

6.36% of OZ shots are taken from the East wing with a goal probability of 2.62%.

Most of the shots from this area are wrist shots with 61.94% of shots and 50.05% of goals scored from the East wing. 46% of shots and 58.43% of goals come from left-shooting players and 54% of shots and 41.57% of goals come from right-shooting players. Right-handed players do shoot much more in this zone, but aren't nearly as effective as they are in the West wing.

 #9 - West Crease

The West crease is an area between the home plate and the West wing as well as next to the net behind the goal line. The reason why the area behind the goal line was included in the West crease's limits is because shots from this area all tend to be of the same nature. Without any good angles to release a shot that will likely be a good, shooters in this area tend to exploit goaltending mistakes to squeeze the puck into the net. If it's a quick reception from the opposite side of the ice to take advantage of the goaltender's lack of speed in getting across his crease or if the goaltender's positioning isn't optimal and the puck finds a way into the net, most shots from the West crease are highly dependable on the opposing team's netminder. The same applies for the small area next to the next, for wrap-arounds or squeezing the puck between the goalie and his post. Although highly dependent on the goaltender's placement, the West crease area has a greater goal probability than the West wing because of its proximity to the net which doesn't allow the goaltender much time to react.

Only 3.01% of OZ shots come from the West crease with a goal probability of 6.12%.

The most common shot type from this area are wrist shots with 61.69% of shots and 59.44% of goals. 59.41% of shots and 52.68% of goals come from left-shooting players meaning that 40.59% and 47.32% of goals come from right-shooting players.

 #10 - East Crease

Just like the West crease area, the East crease has the same proprieties.

The East crease sees a little more shots than the West crease with 3.80% of all OZ shots and a goal probability of 6.49%.

The most common shot type from this area are wrist shots with 55.11% of shots and 56.90% of goals. Left-handed players tend to have more success in this area with 70.95% of the goals scored from 66.06% of the total shots taken in the East crease. Right-handed players scored 29.05% of goals from 33.94% of total shots.

 #11 - Behind Net

Although not the ideal spot to shoot the puck, there are still goals that originate from behind the net. Goals scored from this area are either happy accidents, ultimate precision shots or happy accidents that the shooter pretends are due to his ultimate precision.

There aren't many shots that come from above the goal line, in fact 0.33% of OZ shots come from that area. It could seem strange that 8.98% of shots behind the net resulted in a goal, but that number does make sense considering the location of the shot. Typically, when a player has the puck behind the net, they won't try and shoot it as it would usually end their team's possession of the puck. Instead, players with the puck behind the net usually try to either get into a better position for a shot on net or make a pass. However, sometimes a golden opportunity may present itself to shoot the puck off of the goaltender which would then bounce into the goal. Hence why the goal probability is decently high since players won't shoot unless they truly believe they have a chance at scoring a goal. No matter how you take this information, the probability that an OZ shot was taken behind the net and resulted in a goal is only 0.03%.

Wrist shots are the most common shot type in this area with 61.56% of shots and 61.23% of goals. 61.29% of shots and 62.71% of goals come from left-shooting players and 38.71% of shots and 37.29% of goals come from right-shooting players.

Final words

As we try to extract every possible variable from shots to discover where and what the ideal shot is from and looks like, I believe my OZ shooting areas design is a helpful tool to get a good understanding of every possible location a player can shoot from in the offensive zone to evaluate their shots' effectiveness.

Please feel free to contact me if you have any questions, objections or comments about my design - I'm always ready to talk about hockey!