from Andrew Berkshire at The Sporting News,

I’m beginning to wonder if defensive coaching has hit its limit. It’s always easier to prevent scoring chances against than it is to create them. A huge percentage of defense at the pro level is systemic, attention to detail and funneling attackers to where you want them with five-man units.

Offense, however, requires skill and creativity to break those defensive systems. If defensive systems have hit their peak in NHL hockey, and coaches are always trying to improve their teams, there is likely to be an increased focus on breaking those systems.

One way to test this idea would be to look at how much offense is generated on average over the last few years, and shots on net have risen by just over two per game per team since 2015-16. Alongside shots on net, teams are averaging three extra scoring chances each per game as opposed to two seasons ago, and 1.2 more high-danger scoring chances each per game.

This could be a weird coincidence, but on average all those offensive metrics have risen in each of the last two seasons, at even strength and in all situations. That tells me there’s something more to this increase in scoring than just calling more penalties. It could be the new normal, which is good for the league, since two years ago they were staring down the lowest-scoring season since the dead puck era.

more with graphs, numbers, etc....