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Plus/minus is a bad statistic and you shouldn't use it

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Plus/minus is at best, misleading, and at worst, a completely useless statistic.

Claus Andersen

In Monday night's 7-1 blowout loss to the Tampa Bay Lightning, almost everything is worth ignoring. Blowout games both for and against a team rarely tell you much about either team playing in them. The Lightning outplayed the Canadiens, especially on special teams, but they also scored on nearly 18% of their shots on goal, a rarity in the NHL. Sometimes the puck bounces one way, sometimes others.

Over short samples, this can lead to extremely misleading statistics if you don't know what to look for, the worst of which is plus/minus.

On a post-game show following the Canadiens loss, someone asked why the Habs' fourth line got nearly the same amount of ice time as the third line, with another panelist commenting that it was probably because the line of Rene Bourque, Lars Eller, and Jiri Sekac were -3 on the night. It was remarked that even if a goal against isn't automatically everyone's fault, if you're -3 you're doing something wrong.

Focusing on plus/minus over the course of an entire season can lead to bad analysis, but in a single game it's just plain foolish. I couldn't remember Eller's line looking bad on any goals, and looking at the possession stats, they had a pretty good night in really tough assignments, so I took to video to see if I missed something.

Goal against one

Awkwardly cut by NHL.com, but I managed to grab most of the whole play here. Lars Eller puts good pressure on Anton Stralman, forcing him into a turnover right to Rene Bourque, who breaks in and fires a hard slapper from a pretty bad angle. Ben Bishop stops it, but is a little stunned, and Eller gets a quick scoring chance. Bourque grabs the loose puck and sends it along the boards to Mike Weaver, who misses it.

In what should be a nothing play because Jarred Tinordi has position on the Lightning attacker who's ahead of Weaver and has an easy lane to the puck, Carey Price darts out to try to clear the puck himself, which hits Weaver and stays in. Complete chaos ensues, with a scramble in front of the net, and after being pushed in by a pile of bodies, Vladislav Namestnikov takes advantage and essentially hooks Price to prevent him from making a save. The goal counts because this kind of play is chaotic and tough for officials at the best of times, and it's a coin flip anyway, but there's really no fault to be found for the Eller line on the play.

Goal against two

Alex Galchenyuk is forechecking to allow a line change, and he actually successfully disrupts Victor Hedman, but the puck bounces funny and stays with him, putting Galchenyuk out of position. In the midst of a line change, Hedman sends a bullet pass up to a cherry-picking Stamkos, who is onside, in spite of the complaints of Habs fans.

onside

It was a great, heads up play from Hedman and Stamkos taking advantage of a fluky bounce on a line change, again, nothing the Eller line could really do here. Andrei Markov and P.K. Subban probably shouldn't have let Stamkos get behind them, but this is the second period with the long change, and I doubt they just didn't notice him, it was just an ugly change. These things happen against elite players, unfortunately for these two on this day.

Goal against three

NHL.com doesn't show what led up to this, but the Eller line and Subban did some good work in the offensive zone and got a couple good looks before being beat to a loose puck where Eller couldn't quite get his stick on the clearing attempt from Matthew Carle. It was the end of a long, physical shift for P.K. and with the game at 4-1 already, he kinda just gives up on checking Callahan and gets turnstiled.

It's an ugly play from Subban, the kind that will likely be played on highlight reels all season long from people who want to highlight how 'bad' he is defensively. Ideally he would have taken the body on Callahan, which he looks like he's going to do for a second, but he's just caught flat-footed and tired.

Again though, what is the involvement of Eller's line on the goal? Where is the fault? On all three goals, none of the forwards did anything that could be said to cause the goal against.

So why so little ice?

It could be argued that Michel Therrien saw that line get scored on three times and played them less, but as much as you may not like Therrien, or his strategies, he's not stupid. The coaching staff reviews goals between periods, and I doubt he looked at those goals and thought that line was killing them. Therrien's staff may not use analytics, but I highly, highly doubt they are so simplistic as to judge their players by plus/minus in single games, that's a severe underestimation of their intelligence.

The more likely explanation of why the third line's ice time was so low? Michel Therrien commented after the game that the team didn't have "spirit", like they had against the Flyers. Whatever that's supposed to mean, it probably means he didn't think they were playing with pace. Therrien is an old school guy, and he clearly believes that the fourth line can set the tone for games, so he played them more. Why was it the Eller line that got more time on the bench? Because they haven't scored yet this season. Pretty simple.