One of the best parts of looking at data and statistics is that you can challenge certain assertions that are held commonly by most people.
Recently, the claim that everyone is taking for granted is that Raffl has made the top line better. The Raffl injection has seemingly sparked Giroux and Voracek, both of whom have 2 goals and 3 assists in the past three games.
And so, I'm about to make a claim that I'm guessing 95% of you will disagree with me on, and I am confident that even after I lay out my reasoning most of you still won't agree with me.
Raffl joining the top line may actually be hurting the top line's performance.
Since Raffl has joined the top line, both Giroux and Voracek have a negative Relative Corsi close percentage (Relative Corsi is just a measure of how a player performed compared to how his team performed with him off the ice).
For the season, Voracek has a Corsi close percentage of 56%, and a Relative Corsi close percentage of +6% (meaning when Voracek is on the ice in close situations, the Flyers gain 6% more of the total Corsi attempts compared to when he is off the ice). During the last three games, Voracek has a Corsi close percentage of 50% and a Relative Corsi close percentage of -11.7%.
We see the same trend in Giroux, though a little less pronounced. Giroux's Relative Corsi close percentage this season is +1.9%, but during the last three games with Raffl it has been -2.5%.
So what does this mean? In the last 3 games, the Flyers have actually been winning the Corsi battle more decisively when Giroux and Voracek are off the ice, not on it.
One important note
The Flyers played the Capitals twice and the Canadiens once in the past three games. Neither the Capitals (Corsi Close percentage of 47.5%) nor the Canadiens (Corsi Close percentage of 48.4%) are very good possession teams, and it has showed, with the Flyers having more shot attempts in close situations than their opponents in all three games. So while both Giroux and Voracek have a Corsi close % of at least 50%, the other lines have been dominating possession as well (and to a further extent than the top line has).
But the above numbers don't line up with Giroux's and Voracek's goals/points production. Why is that? Well, it leads us to the inevitable discussion on shooting percentage. I talk a lot about luck or random chance in my comments and posts, so this time I am going to try and different avenue. Hopefully this one makes more sense to those who are resistant to terms like luck and randomness.
At even strength, Giroux and Voracek has been on the ice for 6 goals for and Raffl has been on the ice for 5 goals for. The Flyers have taken 25 even strength shot with Voracek on the ice, 28 shots with Giroux on the ice, and 28 shots with Raffl on the ice. So very clearly, the Flyers have been converting on their chances with the top line out on the ice. The Flyers are shooting 24% at even strength with Voracek on the ice, 21.4% with Giroux on the ice, and 17.8% with Raffl on the ice.
In earlier posts, I might have yelled, "That's lucky. It will end!!!!". But instead, I am going to put it slightly different. The Flyers top line has been converting on their shots in the past three games. Let's give credit where credit is due. However, do we really think that they are going to be shooting 20% at even strength for the rest of the season? Of course not, that's generally not how the game works, unless your name is Steven Stamkos (and even he doesn't come too close to 20%, and that includes power play shots where Shooting percentage increases).
The Flyers top line has been burying their shots, but eventually they are going to go through games where those same shots don't go in. Anyone who's played hockey knows this is true. I just hours ago played a game where I jumped in on a rush and rang a shot off the post. Did I beat the goaltender? Yes. But the shot just didn't go in. Next game I might do the same play, make an identical shot, but this time it goes off the post and in. This happens to every player in the NHL, including to a guy like Evgeni Malkin, who went through a long goal drought to start the season.
So if we accept the premise that the top line is not going to shoot at an abnormally high rate, than it makes sense to look at their possession statistics to see whether or not they truly dominated the game or they just buried their chances that game.
As we saw above, the Flyers top line has actually not been dominating possession as well as the rest of the team. Meanwhile, Hartnell, who Raffl replaced on the top line, has been dominating possession as if he was still playing with Voracek and Giroux. In the last 3 games, he has a Corsi close percentage of 67.6% and a Relative Corsi close percentage of +13.11%.
Now there is one huge caveat to this whole discussion. Even if Raffl is bringing the top line down a bit with his play (as is my perspective), Hartnell moving down to the second line may boost the 2nd line's play enough to offset and overcome any drop in shot differential dominance by the top line. In other words, replacing Hartnell with Raffl may make the 1st line worse but make the team as a whole more balanced and stronger.
I'm not saying this is definitely happening. After all, we only have 3 games of data to look at, and while Corsi adds events to make smaller samples more telling, 3 games is a small data set even for Corsi.
However, I think that this is something that we as fans should be cognizant about going forward. The goals are great, but sometimes it takes a deeper look into the numbers to truly determine how changes have affected a line and a team.