Analytics

Why Individual Plus-Minus is a Useless Statistic

January 26, 2016, Pittsburg, PA-- Phil Kessel #81 of the Pittsburgh Penguins skates with the puck against the New Jersey Devils at Consol Energy Center in Pittsburgh, Pennsylvania. (Photo by Matt Kincaid/Getty Images)
Why Individual Plus-Minus is a Useless Statistic
Jessica Pincente

Individual player plus-minus is a horrible statistic.

You may have heard similar sentiments before, but most of these statements usually come without a decent explanation as to why plus-minus is actually terrible.  Well, look no further!

Plus-minus is essentially an individual player’s on-ice goal differential.  If a player is on the ice during a goal-for, they receive a plus-1.  If they are on the ice during a goal-against, they receive a minus-1.  This stat has a special place in the hearts of many people, as plus-minus was one of the very first “advanced stats.” Sorry, guys. It’s awful.

THE ISSUE

The main problem with this statistic is that it measures the events happening around a player, and not the player’s contribution to those events.  In many cases, a player will receive a minus-1 during plays in which they did not even touch the puck.  As we know, goals can result from a multitude of different mistakes. An individual player can do everything right — block a shot, cover their man, back-check, etc. — and still receive a minus-1.

Here is an example of a player receiving a minus rating on a goal-against in which he had no contribution to. This goal is from the Pittsburgh-Ottawa game on Tuesday, April 5th. Pay specific attention to number 6 of the Ottawa Senators (Bobby Ryan) on the left.

analytics, plus-minus

Video courtesy of the National Hockey League.

Screen Shot 2016-04-06 at 10.37.28 AM

Ryan did everything right in this play.  He was in proper position- Ryan was stationed as the forward at the top of his defensive zone in order to cut off the passing lane between the two Pittsburgh defencemen.  He does not touch the puck at any point during the play, yet still receives a minus rating for a goal-against in which he took virtually no part in.

NHL RANKINGS

Here is a list of the 15 worst individual plus-minus rankings in the NHL (As of April 8th, 2016):

plus-minus, analytics

Notice that only one of these 15  players is on a playoff team (Patrick Marleau of the San Jose Sharks sits at seven).  Notice again that four out of 15 players play for the Vancouver Canucks.  Realistically, this says more about the Canucks than it does about those individual players.  Have you ever heard anyone say Bo Horvat or Radim Vrbata are bad players because of their horrible plus-minus’?

Finally, notice how highly-coveted trade deadline bait, Mikkel Boedker, is tied for the league’s worst plus-minus rating.  Keeping in mind that he has played on the Arizona Coyotes and Colorado Avalanche, his trade value was not hindered by this statistic whatsoever.  Arizona received great return for Boedker, and he has played well for the Avs since his trade.  His plus-minus is practically irrelevant.

FURTHER PROOF

Incase you haven’t realized how horrible individual plus-minus truly is, here are two more examples.  Connor Brown, drafted in the sixth round of the 2012 NHL entry draft, was a minus-72  in his draft year. That must mean he’s a horrible player, right? Wrong. At the time, Brown was playing for the pre-Connor McDavid and Dylan Strome Erie Otters.  The Otters finished dead last that year with 10 wins in 68 games.  Fast forward 2 years, and the Otters are back into playoff contention.  Brown, along with Connor McDavid and Andre Burakovsky, resurrected the Otters.  In the 2013-14 season, Connor Brown scored 128 points (in 68 games) and had a plus-minus rating of plus-44.  Brown’s plus-minus increased by 116 in two seasons.

Another less-dramatic example of a case similar to this is that of Phil Kessel.  Kessel, playing for the Leafs, had a plus-minus rating of minus-34 in the 2014-15 season.  He also had 61 points in 82 games.  This season, Kessel had the opportunity to play with some of the best players in the world in Pittsburgh and saw significant improvement in his plus-minus rating (plus-9 in 2015-16).  Some might say he had a better year, but his numbers are very similar to those of last season.  He scored at a very similar pace, tallying 59 points in 81 games this season.

In both of these cases, the reason behind each player’s jump in individual plus-minus is a change in teammates.  A successful team’s players will have mostly positive plus-minus ratings, while a bad team’s players will usually have negative ratings.

SO, WHAT IS THE POINT OF PLUS-MINUS?

When used in the context of team goal differential, plus-minus offers insight into how good a team truly is.  Although a simple measurement, team goal differential speaks wonders.  Out of the 16 teams that have qualified for the NHL’s postseason, only one of those teams currently has a negative goal differential — the Detroit Red Wings sit at a minus-12.  Every single team who did not qualify for the postseason has a negative goal differential as well.  You have to score more goals than your opponent if you want to win, kids.

All in all, individual plus-minus is a useless statistic.  In no way does it measure a player’s individual contributions, which is essentially what player statistics should do.   When put into context, plus-minus can measure the effectiveness of a team throughout a season.  This is it’s only true use, though.  Using plus-minus to evaluate individual players is incorrect and ineffective analysis. Sorry, NHL.

All statistics provided by the NHL’s official stats page.

 

 

  • Johnny Canucklehead

    You should go on amazon and check out Klein & Reif’s Hockey Compendiums. They’re old books but their adjusted plus-minus made sense to compare players on good vs bad teams.

    For example a player who is even on a team that is -50 would be equivalent to a +10 player on a team that is even GF/GA.

  • Johnny Canucklehead

    You should go on amazon and check out Klein & Reif’s Hockey Compendiums. They’re old books but their adjusted plus-minus made sense to compare players on good vs bad teams.

    For example a player who is even on a team that is -50 would be equivalent to a +10 player on a team that is even GF/GA.

Analytics
Jessica Pincente
@jesspincente

Beat writer for the Brampton Thunder of the CWHL. Just a fan of the game.

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