Hanging on to the possession numbers

Jesse Puljujarvi, Ryan Strome, Scott WilsonThroughout the Oilers struggles this season, I’ve looked at the underlying shot-share numbers and held out hope for this team. As long as the even-strength (5v5) possession numbers are good (i.e., Corsi and Fenwick) I’ve figured that the goal-share should eventually turn around. This of course depends on the team’s shooting percentage regressing towards the league averages and the goaltending bouncing back as well. And they’ll also need their special teams to stop costing them games.

Corsi For% Fenwick For% Goals For% Shooting% Save% PDO
53.04% 52.88% 45.56% 6.57 91.19 97.8

After 23 games, the Oilers are fourth in the league when it comes to score-adjusted Corsi For% and fifth in the league when it comes to Fenwick For%. This is all very encouraging until you look at how the team has been trending when it comes to these possession numbers.

Below is a rolling 10-game average of the Oiler’s Corsi For% and Fenwick For%, adjusted for score effects. The team has trailed a lot this year, which skews the shot-rate results. So I’ve applied Natural Stat Trick’s weightings.

RollingCFFF_20171125

  • Corsi For% (CF%) – The proportion of all the shot attempts the team generated and allowed that the Oilers generated (i.e., Corsi For/(Corsi For + Corsi Against). This is used as a proxy for possession and can predict a team’s future share of goals.
  • Fenwick For% (FF%) – The proportion of all the unblocked shot attempts the team generated and allowed that the Oilers generated (i.e., Fenwick For/(Fenwick For + Fenwick Against). This is used as a proxy for shot quality and considers shot blocking a repeatable skill. It can also predict a team’s future share of goals, slightly better than Corsi.

While the team started extremely well early on posting close to a 55% shot-share, they’ve dipped down closer to 50% over the most recent 10-game stretch. My first thought was that this was a depth issue which has struggled this season, and that the numbers were probably trending just fine with McDavid on the ice. Unfortunately, it looks like it’s a team-wide problem. With and without their captain, the Oilers have trended downwards, which indicates that this is likely a coaching/deployment issue.

RollingCF w97_20171125

RollingFF w97_20171125

After such a bad start, it’s understandable that McLellan may have changed up his tactics even if the team was posting strong possession numbers. The end-goal is winning games, and I can’t imagine a coaching wanting to wait things out in the hopes that things get better. McLellan also adjusted his deployment, especially on defence as Klefbom was moved away from Larsson on the top pair and saw his overall minutes reduced.

Below is a chart from Hockey Viz showing the ice-time for each Oilers defenceman this season. Note the drop in ice-time for Klefbom who has struggled mightily.

edmonton oilers defence hockey viz

If there’s a single player that can influence play and drive the offence for the team, it’s Klefbom. Reducing his minutes is necessary for the coach, but it might be the biggest factor in the Oilers drop in possession numbers. The team was  doing something right when Klefbom was on the ice earlier in the season, so it’d be interesting to see what the results would be if he was paired with Larsson on the top pair again. The two were very good together last season, regularly playing against the best lines.

For my own interest, I also wanted to see how the rest of the Pacific division was trending when it comes to Corsi For%. Below I’ve split each team’s season into two (first 10 games, and their second set of 10 games).

Pacific Division - trend - 20171125

Edmonton saw a drop over their last 10 or so games, but so did a lot of the other teams. Vancouver and Arizona are where I expected them to be. San Jose and Calgary are playing well. What really stands out are the numbers for Vegas. The Golden Knights were riding a pretty high PDO earlier in the season, but they’re closer to the normal range now. I think a lot of us assumed they were going to coming crashing back down to earth, but I’m not so sure any more. If they continue posting strong possession numbers, they increase their chances of putting more points in the bank.

Data: Natural Stat Trick

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