A Quick And Dirty Look at the Value of a Goal, Or Alternately: Luck Matters

Scotty Bowman said something more than thirty years ago that occasionally seems to be at odds with conventional wisdom, but meshes well – even obviously – with reality.

Bowman said that in 1976; it’s something that should be obvious based on how hockey games have unfolded over the years, but all too often it seems that the role of injuries, bounces, refereeing and all other manner of luck is ignored.

Luck is reduced in the regular season, because of the large number of games played, but it isn’t entirely eliminated. Consider goalposts as an example. Last season in November, the Rangers had hit 8 more goal posts than their opposition. Meanwhile, the Oilers had seen their opposition hit 12 more goalposts than they did. Imagine what an effect switching those numbers would have had on each team’s season – that’s a 20 goal swing, by November! Checking in again in February, we have an expected outcome – the margin has increased, albeit at a slower rate. Now the Rangers have hit 14 more goalposts than their opposition, while the Oilers have seen their opponents hit 16 more than they’ve hit themselves – a 30 goal swing. That’s a 6% impact on the outcome of the season at the extremes right there; the difference between making the playoffs and missing them, or the difference between making the playoffs and winning the division. Of course most teams fall into the middle of the spread, so this effect is minimized, but in certain rare instances could result in massive swings with precisely the same amount of talent and level of opposition.

In any case, those are groups of goals, and a single lucky goal has virtually no impact on the regular season. The average NHL team this year saw 478 goals scored for and against, meaning that a single goal on average had a .2% impact on the outcome of a season.

Now, consider a playoff round – it’s a completely different story. Here are the playoff series from the first round, with total goals scored for and against in each of them:

In each series, on average, a total of 28 goals were scored. That means that a single lucky goal, or a bad call leading to a goal, or a goal post, or whatever would have roughly a 3.6% effect on every series. It would only take three good bounces to have a greater than 10% sway on the outcome of each series, on average.

All of this tells me that what Scotty Bowman had figured out more than thirty years ago is absolutely correct – luck has a huge outcome on the result of a single playoff series. Since it requires four series to win the Stanley Cup, that level of luck is compounded. The best team should win, but with a couple of bounces one way or the other a team that should have won the Stanley Cup can end up ousted in the first round.

I’d even argue that there’s no such thing as a “team of destiny” any more; every year there are a half-dozen good teams with legitimate shots at the Stanley Cup, and with a little bit of luck any of them could win it all.  These aren’t the days of the Original Six.