I won’t be quoting any numbers or arcane stats in the post today. I won’t even be contributing much original material. Mostly I just wanted to call attention to this interesting article by David Staples of the Edmonton Journal on the history of scoring chances and "non-traditional" stats in the NHL.
The secret statistics – most notably the individual scoring chances stat – are tracked by coaches on each team. They’re used in games to make between period tactical adjustments and in video training sessions to help players understand what they’re doing right and what they’re doing wrong. They’re also used by NHL general managers to evaluate players and make trades. It’s not so simple to know exactly when these secret stats — or alternative stats as I call them — became widely used in pro hockey, but there’s little doubt that Hall-of-Fame coach Roger Neilson was a key innovator.
Neilson developed a systematic way to keep track of scoring chances and also to keep track of which players helped create those chances and which players made mistakes on chances against.
Neilson created a scoring chances sheet, which was photocopied and passed on for decades to various coaches. It had a line down the middle. On one side, he or an assistant would record each scoring chance for, with a plus mark for only those players involved in the chance. On the other side, they would record chances against, with each player who made a mistake getting a minus mark.
One thing I get asked a lot when it comes to "new stats" (misnomer!) is whether NHL teams actually use any of them or not. The truth is, much of this stuff is old hat to many NHL coaches and teams. Corsi was named after the NHL coach that came up with it, for example. Neilson has been tracked scoring chances and grading players according to their chance differentials since the late-70’s. We’re just kind of stumbling on stuff that smart men in the NHL have known about for about three decades.
Neilson defined a scoring chance as a dangerous shot from a zone in front of the net. For his boundary, he drew a line back from the side of the goalie crease to the faceoff dot, then straight back to the blueline. But any shot that came from the point in this scoring chance zone either had to be screened or tipped to count as a scoring chance.
This is fairly in tune with the chance definition we use here at FlamesNation use when counting chances. I was never overly anxious about it, but it’s nice to know we’re in line with Neilson here. Staples notes that Neilson sometimes included "chances at chances" (for example – a two-on-one that doesn’t result in a shot on goal), but I’m comfortable in excluding them nonetheless.
“You see value in players other people don’t see. Because some people only see goals and assists and flashy plays. They don’t understand what a guy can do for you in a certain role. So it does give you a little clearer picture, for the coaches and the manager of the team to know what you’ve got.
That’s Staples quoting Dave King, former Flames coach and a Neilson disciple. The rationale for tracking scoring chances noted by King here meshes with a lot of what we talk about in terms of SC’s and new metrics: finding the value (or fault) in players that can be missed by perception and observation alone.
Things are so advanced now, King says, that all NHL teams have a video coordinator and coaches assigned to video analysis. The chances stat is used in making major decisions. “Sometimes these stats factor in for decisions on players. There may be a player who has reasonably good numbers in terms of goals and assists, but when you really look at his game and you can see he’s a player who is a real negative chances guy, that sometimes weighs into a decision on making a trade with another team.”
Emphasis added by me. King doesn’t use the terms like variance, luck or the percentages here, but it’s clear that’s what he’s talking about (even if he doesn’t use the mathy words). If anyone wonders we bother with PDO (SH% + SV%) or why I looked at goals% versus scoring chance% for the Flames recently…this is it.
NHL teams keep this data secret, King says, because they believe they have something of value that their competitors do not have. “We guard the information carefully.”
Too bad we’re giving it away for free around here*…
*(if we don’t do scoring chances next year, you can be reasonably sure we’ve been bribed by the Flames to shut-up. Or threatened with physical violence).