Why are goals up across the NHL? No matter where you look, offense has been winning the age-old battle this season with no signs of slowing down. After a long offseason of pundits complaining about the Ottawa Senators’ trap style, claiming the nets should be smaller, and even suggesting that the rulebook be changed (more on that in a bit), defenses have allowed more goals, shots, and chances than they did last year.
What may be the most remarkable thing about all of this is that it has been so unexpected, and Vegas has failed to capitalize. At the sportsbooks, it is rather common for casual bettors to take the over, and in hockey that is no different. Historically, betting the over has been a losing strategy, with a return on investment of between negative two and three percent per season.
Data courtesy of BetLabsSports.com
But this season, for the first time in years, overs are hitting more than the unders. If you had wagered the same amount on the over in every NHL game this season, you would be up.
What Is happening, and Will It Last?
It’s not that the bookmakers are just setting bad lines and being taken to the cleaners by smarter, much more attractive gamblers and FantasyLabs writers and subscribers. Goals really are up, and in a substantial way.
| CF/60 | SF/60 | GF/60 | xGF/60 | xGF/Shot | GF/Shot | |
| 2016-17 | 54.47 | 29.27 | 2.64 | 2.66 | 9.09% | 9.02% |
| 2017-18 | 58.02 | 31.46 | 2.86 | 2.87 | 9.13% | 9.08% |
| % Change YoY | +6.5% | +7.5% | +8.3% | +8.0% | +0.5% | +0.7% |
There are a handful of things to note about this table.
- All data here are from the wonderful Corsica.Hockey, a great data source if you ever want to dive deeper into hockey.
- This is for all situations for the entire league. It hasn’t been adjusted for score. Data for 2017-18 includes up to and through the NHL action on February 26.
- With increased shots and shot attempts (SF and CF, respectively), it is no wonder that goals are up as well. But goals are up — on a percentage year-over-year basis — more than just the shot metrics would indicate.
- xGF/60, standing for “expected goals per 60,” takes into account the likelihood of every shot going in the net according to where on the ice it was taken (and a few other things, such as whether it is a rebound opportunity or not). This metric (my preferred method of analyzing NHL performances) shows a similar trend: xGF/60 has increased more than SF and CF. Not only are more shots being taken, but more dangerous shots are being taken.
- Goalies are letting in roughly six shots per thousand more in 2017-18 than they allowed in 2016-17, which doesn’t seem like a lot, but when 20 shots per thousand is literally the mark between a bad NHL goalie and a great one (90.5 Sv% vs 92.5%) six shots is a big deal. However, as shown by “xGF/Shot”, this increase is mostly due to the fact that the actual shots faced by the goalies are better in quality and thus more difficult to save.
In summary, defenses are allowing more chances to score. These chances are more dangerous than they’ve been in the past. And goalies are doing a (slightly) worse job at preventing goals even when accounting for this increased difficulty. These trends hold at full strength, so an increase in the power play isn’t responsible for the boost.
Why Is This Happening?
This is a question that is trickier to answer. One theory is that the NHL is a copy-cat league, and the back-to-back reigning Cup Champions are one of the most up-tempo teams in the league. The Pittsburgh Penguins over the past three seasons rank in the top 10 in every offensive category (leading in xGF/60 and just behind the Capitals in GF/60 with top-10 shot metrics as well). It helps that they have two of the best players in the league in Sidney Crosby and Evgeni Malkin, but their success paves the way for teams to incentivize their talented players to push the pace and produce offense.
The NHL may have provided some incentive to feature skill as well, having emphasized during the preseason to the referees that no longer would players be subject to slashes/hooks around the hands. This infuriated defenders to begin with, but the increased level of stick infraction enforcement has had a doubly important impact on scoring. Across the NHL, penalties per game called for slashing/hooking are up 18 percent, with an extra penalty being called for every three games played. While this is a substantial increase, this may not even be the most impactful aspect of the rule change.
| DKPts by Forward Line | 2016-17 | 2017-18 | YoY Inc in DKPts/GP |
| Top-Six Forwards | 2.82 | 3.04 | 8% |
| Bottom-Six Forwards | 1.65 | 1.71 | 4% |
| % of DKPts to Top-Six | 63.1% | 64.0% |
With this emphasis on stick infractions, talented players of the world (such as Johnny Gaudreau, who had his fingers broken by a rogue slash last season) are able to stickhandle in a more creative fashion, leading to more time spent with pucks on sticks and more offense generated by the star players, which is why the increase in scoring has been disproportionately skewed to the top lines (as seen in the table).
I’ve used the FantasyLabs Trends tool to separate the top forwards from the bottom forward by lines, which is a decent proxy for “stars” and “not stars” with a few exceptions. While both groups have increased their output since last season, the overarching trend is rather exciting. Perhaps due to 1) an emphasis on offensive creativity brought about by the Penguins’ success, 2) an increase in power play opportunities due to stricter enforcement of the rules, and 3) an inability on the part of defenders to adjust to a less slashing-friendly environment, star players are excelling this season in a way that is noticeably different from years past.
If the league is committed to putting a free-flowing game on the ice, we may continue to see more overs than unders in the future.
Photo Credit: Patrick Gorski-USA TODAY Sports
