( Photo Credit: Matt Stone/MediaNews Group-Boston Herald )

By: Lydia Murray | Follow Me On Twitter @lydia_murray12

A few weeks ago, I published articles on how the Bruins were offensively and defensively this season using shot heatmaps. You can find those here and here, respectively. They haven’t looked like that team since returning to play, but I’m not worried about that given the exhibition-like nature of those games. The real ones start tonight, as they face off against the Carolina Hurricanes in Game 1 of the first round of the playoffs at 8pm.

Before the game starts, I wanted to take a look at how they were on the power play (PP) in the regular season. It hasn’t been productive at all since play started back up, but hopefully they can turn it around soon. I have faith they will, because as you’ll see, it was outstanding during the regular season. These next two sections are taken directly from the two articles from earlier, so if you’ve already ready them, feel free to skip. If you haven’t, or just want a refresher, read on!

Please note, these graphs are just from the regular season games, so they do not include the round robin games. I will also just be analyzing the play of the PP from before the pause. Finally, I will mainly be mentioning the first power play unit when I break down the spots, which typically consisted of David Pastrnak, Patrice Bergeron, Brad Marchand, Jake DeBrusk, and Torey Krug. This is because they were the most consistent unit in terms of personnel, and they got the majority of the ice time on the PP and were easily the most productive. But, these heatmaps are not only of the first unit, so keep that in mind when you’re looking at them.

A Short Introduction to Shot Heatmaps

Before I begin, here’s a short overview of how to read these heatmaps for those of you who don’t know or need a refresher. This is just a basic overview of how these heatmaps work. If you want to see a really in-depth analysis, you can check one out (albeit of the San Jose Sharks) here. But anyway, these maps illustrate the number of unblocked shots (not necessarily on goal) for or against a team compared to the league average, and where those shots are coming from. Blue means that fewer unblocked shots are generated from a given spot than the league average, whereas red means more are generated than the league average. The deeper the color, the further away from the league average a team is from that spot. White means that shots are being generated at the league average from that particular spot. 

With this in mind, on offensive graphs, blue is good, and red is bad. Obviously, you want your team to be generating a ton of shots, and ideally, they’ll be producing more than most other teams. On the other hand, for defensive graphs, the opposite is true. When an area is blue, it means that team is letting less unblocked shots through than the league average. It goes without saying that’s a great thing. The fewer shots that get through unblocked, the fewer chances an opponent gets to score. 

Defining Areas of the Ice

Heatmap Taken From HockeyViz.com Courtesy of Micah Black McCurdy

Before I get started with the actual heatmaps, there’s just a few more things I want to go over. Pictured above is an example of the heatmaps you’ll see in this article as it was directly on the website. This is great on its own, but I decided to add a few more things to aid in my analysis.

Original Heatmap Taken From HockeyViz.com Courtesy of Micah Black McCurdy

As you’ll see, I’ve added a box and a trapezoid to the above graph (as well as made the crease more obvious). My apologies for the subpar photo editing job, I don’t have access to the best software and I’m not too skilled at it either. But, it’s good enough for the purposes of this article. Please note, these outlines may be off a little bit, but if they are, it’s not by much as I was as exact as possible with the tools I had. 

I’ve added these areas to aid in my analysis of these graphs. The box area I have outlined is known as the “slot”, and shots from this area are considered “high danger”. The trapezoid is known as just that, and shots from that area are considered “medium danger”. Shots from anywhere else on the ice are considered “low danger.” According to this article, in the high danger area, shots have at least a 10% chance of going in. The article also says that shots from the medium danger area have a 3-10% chance of going in, while low danger shots have at most a 3% chance of going in. 

To be clear, those percentages are averages, as some shots obviously stand a better chance of going in than others, even from within those areas. For example, a shot from the backdoor of the net that’s wide open has a much better shot than one that’s coming from right out front with the goalie square to it. But anyway, with all of that out of the way now, let’s get into the actual analysis these things.

Now, Onto the Analysis

Original Heatmap Taken From HockeyViz.com Courtesy of Micah Black McCurdy

Almost the Whole Left Side Was Outstanding

The Bruins shot at an above league average rate for almost the entire left side during the regular season. That’s simply incredible. The best spots on the left side were unsurprisingly in Pastrnak’s office, which is the left circle, and particularly any area to the left of the dot. The Bruins shot at a shot per hour rate above the league average in three spots in those areas. To put it in perspective, there’s usually only a couple of shots per power play, and only a couple of PP’s per game. So, to be that much above league average from one spot is absolutely amazing. Again, it’s not overly surprising though given that’s Pastrnak’s office and the Bruins love setting him up for his trademark one-timer on the PP.

The Bruins are also excellent from the left point, which is Krug’s favorite spot. So, again, it’s not exactly surprising they shot so well from there. But, that doesn’t make it any less impressive that they produced at a rate of 0.5-1 more shots per hour than the league average from there. This is especially true considering they already had three spots on the left side where they shot at shot per hour above-average rate. Considering there are usually very few shots on the PP, it’s mind-boggling to think that the Bruins had so many areas of the ice where they are that much above the average in the regular season. It goes to show that they were really that good this year, and not just really lucky.

Bumper Area and Right Circle Were Amazing Too

Another area of the ice where the Bruins were incredible on the PP is the bumper. And yet again, it’s not surprising. That’s Bergeron’s spot, and he’s one of the best power play bumpers in the league. He has such a quick release it’s hard for goalies to make a save, especially considering he’s not that far out. But anyway, as you can see from the map, the Bruins are shooting at a 0.8-1 shots per hour above-average rate throughout most of the bumper area. Just like the left point is made even more impressive by how many other spots on the ice the Bruins were shooting significantly above average from, the bumper is too.

Yet another area of the ice where the Bruins shot significantly above the league average is most of the right circle. That’s primarily Marchand’s domain on the first PP unit, although the Bruins are known for rotating around a lot on the power play, so he’s not the only one who ends up shooting from that spot. If he was, I’d be really surprised the Bruins shot as well as they did from spots over there. Even with that in mind, while I’m really happy about it, Marchand didn’t seem to shoot as much as the others, so it’s a bit surprising. 

Anyway, it’s possible that the league average is lower on the right side than in those spots. This would explain why the Bruins were still so far above the league average when they didn’t seem to take as many shots from that area as they did others. But, that shouldn’t make it less impressive that the Bruins have yet another area of the ice where they were way above the league average.

Right Point Really the Only Spot That Needed Work

Assuming the Bruins PP returns to its regular season glory soon, the only spot the Bruins could really work on shooting more from in the playoffs is the right point. Krug usually stays further to the left, so it’s not surprising there’s a lower volume of shots to the right. However, that doesn’t mean they can’t improve over there. The first PP unit is known for rotating around a lot, so Marchand (or someone else) could easily rotate up there and get some shots off.

If they start shooting more from there, it’d make it so the PKers would have to anticipate that happening and spread their box out more to cover for it. That’s exactly what you want on the PP. The more spread out they are, the more lanes everyone has to shoot through, which should almost certainly result in more goals. So, hopefully once the Bruins’ PP returns to normal, they work on getting more shots off from that spot.


Simply put, this PP heatmap is amazing. This isn’t surprising, given the Bruins had the second-best PP in the league (behind only the Oilers) in the regular season with an outstanding 25.2% conversion rate. So, I expected to see them shooting above average in a lot of places. But, I honestly didn’t think it’d be this good. It’s truly amazing that the Bruins shot as far above the league average as they did from as many spots as they did in the regular season. To only have one significant spot (the right point) where you’re shooting below the league average is incredible. 

It goes to show that the Bruins’ PP was really that good in the regular season, and not just really lucky. That’s why I have faith that the power play we saw in the exhibition game and the round-robin is not the one we’ll continue to see. I think the one we’ve been seeing in these past few weeks was a result of not having a lot of time to practice it and the fact that the Bruins weren’t playing their best. As good as they were, it’s only a matter of time before it returns to its regular-season glory. Once that happens, provided the team picks it up and plays better (which they almost certainly will now that the games actually matter), the Bruins will be in great shape to hopefully make another deep run.

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