Checking in on the Oilers Pacific Division Rivals

Forty games into the 2016/17 season, and the Oilers are holding a playoff spot, ranking third in the Pacific with 47 points, good for fifth in the Western conference. The team is coming off of a big win against a good Boston club last night, with Maroon, McDavid and Talbot leading the way. Up next is a back-to-back set against the Devils, who will have played the night before, and the Senators.

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With the team in a playoff race now, it’s worth checking in on how the Oilers Pacific division rivals are doing in terms of goals and the shot metrics that predict future goals. The three California teams are going to be the ones to beat, but if the Oilers can get consistent even-strength scoring from the lines that don’t feature McDavid, they could potentially challenge for that third spot.

Here’s what the Pacific Division looks like today. I’ve included each team’s record, along with their points percentage, which is the points divided by the total points available (Source: Hockey Reference). I’ve also included the following:

• Corsi For% (CF%) - The proportion of all the shot attempts the team generated and allowed that the team 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.
• Expected Goals For% (xGF%) - This is a weighting placed on every unblocked shot based on the probability of the shot becoming a goal. This depends on the type of shot, location and uses historical shot and goals data to come up with the probability for each unblocked shot. This has been found to be a better predictor of future goals than Corsi and Fenwick. (Detailed explanation can be found at Corsica Hockey)
• Goals For% (GF%) – The proportion of all the goals that the team scored and allowed that the team generated (i.e., Goals For/(Goals For + Goals Against).

What we can also do is look at how each team is doing over 10-game, rolling segments this season. What we do here is take games 1-10, find the average of the metric, then take games 2-11, find the average, games 3-12, and so on. Doing so can highlight trends and can give us a better perspective of how a team’s entire season has been going.

I’ve focused on even-strength play (5v5), as it evaluates a team in a natural game setting where coaches are rolling their lines, trying to score and defend, and is where the majority of the game is played. These numbers are also score adjusted, based on Corsica Hockey’s methodology. This way, we eliminate score-effects, as team’s that trail in a game start to take more risks and generate more shots, while team’s that lead in a game tend to play safer, and generate far fewer shots. Without adjusting, team’s that trail a lot, like the OIlers have in the past, start posting better shot-shares, for example, mainly because they’re taking more risks trying to tie a game. So adjusting for score-effects puts more emphasis and value on the events that occur in close game situations and gives us a more accurate assessment of a team. More on adjusted metrics can be found at Corsica Hockey.

Goal-share (GF%)

First, let’s start with each team’s rolling-10 game average of goal-share at even-strength. The Oilers have scored 75 goals and allowed 69 this season, so of all the goals scored and allowed the Oilers have 52.38% of them. In the Pacific division, they rank 2nd in terms of goal-share, and 4th in the Western conference.

Corsica Hockey

The Oilers (red line) have done well here over the course of the season compared to Anaheim, Los Angeles, San Jose and Calgary. San Jose was able to maintain a goal-share above 60% for an extended period of time, but that appears to be cooling off. It appears Calgary (in green) and Anaheim (blue) had struggled early on with their goal share, but have been able to stay around the 50% mark.

Scoring goals is the objective, but a team’s current share of them isn’t a very good predictor of future success. Goals don’t happen very often, and when they do, there’s a lot that has to go right for a shot to become a goal. We see that in the rolling average graph above, as each team’s goal-share fluctuates quite a bit. What we can do to predict future success, in terms of goal-share, is to look at the team’s share of shot attempts at even-strength (i.e., Corsi data).

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Corsi For% (CF%)

When it comes to the share of shot attempts (CF%), the Oilers rank 12^th in the league with 51.10%. If we look at each of the five team’s rolling 10-game averages this season, we see that the Oilers (in red) have been trending downwards, and have posted a very poor 47% share of shot attempts over their last 10 games.

Corsica Hockey

The Kings (in purple) are in their usual spot sitting near the top of the league when it comes to Corsi For% with 54%, and have been able to maintain that through the season. The Sharks, Flames and Ducks have been hovering around or above the 50% mark over the most recent stretch of games, with the Ducks making the most improvement from early on in the season. What the team’s declining share of shot attempts tells us is that the Oilers are reducing their chances of scoring goals going forward. The good news is that this team is capable of putting together stronger, more competitive numbers, as seen in their early season performance.

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Expected Goals For% (xGF%)

Next, we can look at how each of the five Pacific division team’s are doing when it comes to their share of expected goals (xGF%). As mentioned above, this metric captures shot quality using historical data to give each unblocked shot a weighting, based on the type and location of the shot, and is another predictive metric.

Corsica Hockey

Here we see that the three California teams have been leading the way for the majority of the season, with Calgary (in green) typically below the 50% mark, and Edmonton (in red) trending downwards.

The Oilers currently rank 19th in the league with 49.00%, and have had a share of 43.77% over their last 10 games. This recent 10-game stretch has only been better than the Avalanche’s 10 games, and slightly worse than the Devils’. The Oilers issue this season hasn’t been generating better quality shots, it’s been limiting them. When it comes to expected goals for per 60, the Oilers rank 11th in the league with 2.46. But when it comes to expected goals against per 60, the Oilers rank 26th in the league, with 2.56. Again, this metric is a predictor of future goal share, meaning the Oilers have some work to do, especially when it comes to defending, if they want to ensure a playoff spot in April.

Perry Nelson-USA TODAY Sports

Takeaway

The objective of this is to highlight how the Oilers and their division rivals have been doing over the course of the 2016/17 season, and what areas the Oilers need to improve upon to solidify a spot in the playoffs. The good news is that the Oilers have been getting a higher share goals at even-strength compared to the other teams in the Pacific and have also received excellent goaltending from Cam Talbot. What’s concerning, however, is that the metrics used to predict a team’s future share of goals indicates that the club has issues that need to be addressed. In particular, the team’s share of shot attempts and their share of quality shots, has been trending downwards, with team defence appearing to be a culprit. Failing to address these issues as soon as possible could very well cost the team a playoff spot.

Data: Corsica Hockey