What’s The Deal With The Plus/Minus Statistic?

They say the greatest discoveries happen when you’re not even looking for them. They’re right.

Canadians have been credited with some great achievements in history such as insulin, basketball, and poutine. Now, last night in Nova Scotia, Canada, I discovered the secret of succeeding in hockey. Here is my story.

It started off innocently enough. Much has been made of the Pittsburgh Penguins goal scoring prowess. 60 goals in the month of December alone. 2nd in the league in total goals for. 2nd in goals per game average. 2nd overall in the standings. So it got me wondering, why do they have only 11 players at a positive +/-, and 7 at a negative? How did this compare to the rest of the league top ten? I wanted to know if the +/- stat was useful in any way. Instead I found much more than I bargained for.

I noticed every other team in the top 7 have at least 14 players at a positive as of Tuesday night. 5 of those teams have 15 or more. That’s a pretty big difference from the Penguins. 6 of those teams also had 3 or less players in the minuses.

Digging deeper league wide, I found that generally a team with a goal differential (goals for minus goals against) of 15 or more had 5 or fewer players in the minuses, and 14 or more players in the positives. Teams with a goal differential between 0 and +10 generally had an even split of roughly 9 players plus and 9 players minus. As you can guess, teams with a goal differential of -5 or worse average more minus players than plus.

What that seemed to indicate is if your team scores more goals than the other teams, they generally have more players at a plus than a minus! My radar started to tingle.

Looking further, I was shocked to see 9 out of the top 10 teams in the standings also sit in the top 10 in goal differential (the only exception is Anaheim at 9th with a -2). Oddly enough, 8 of the bottom 10 teams in the standings have 8 of the worst league goal differentials.

It was all unfolding before my eyes. It proved scoring more goals on average than the competition also meant your team won more often. AND it was backed up by the fact that the reverse was true as well. Give up more goals and you are almost certain to lose more! I knew I was on to something.

But could that be a coincidence? Were there any other stats to prove it? Then it hit me right in the face: Columbus has the best goal differential at +50 and sit first overall. Colorado has the worst at -49 and sit dead last. That fits too!!!

I decided to rank the whole league, and that cemented it. 8 of the 10 teams in the middle of the pack have mid range goal differentials.

Team goal differential, with very few exceptions, is the key to NHL victory. I had it. Goal scoring. The secret to hockey!

Now, as for my original high minded goal of finding out if +/- was a worthwhile stat, the above numbers point to a dramatic conclusion: individual +/- statistics are almost always a reflection of the team’s goal differential. As I said, teams that score more goals tend to have more players on the plus side and vice versa. Wierd, eh?

So if that’s true, what about the Penguins and their lower than average number of positive players?

Evgeni Malkin, Connor McDavid and Sidney Crosby are the three top point getters in the league and aren’t in the top 30 for +/-. McDavid and Crosby aren’t even in the top 50! Both are +9 as of Tuesday. How can that be if they don’t suck?

Well, those three players rank in the top 25 in powerplay points. You don’t get a plus for powerplay goals. In fact, 6 of the top 10 power play point getters so far this season are a minus. Of the other 4, three of them play for Columbus, who remember, leads the league by far in overall goal differential and have no one at all over 25 games played in the minuses, so no surprise there. The other one is Victor Hedman at a +6. Tampa Bay is tied for 8th in league goal differential so that also fits.

The Penguins as a team are 3rd in the league in power play goals. It stands to reason they’d then have slightly fewer than normal players in the positives because a higher than average percentage of the goals they score aren’t worth a plus.

So the secret is out. Scoring more than you let in wins hockey, and +/- is a generally meaningless stat. Pass it on.

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