April 14 2012 08:46PM
Earlier this evening, on Hockey Night In Canada, Kelly Hrudy asserted that goals often come at the beginnings and at the ends of periods. Because this seems like the kind of statement that is ripe for debunking, I enlisted the programming help of Greg Sinclair (@theninjagreg) to check on this.
We used four years' worth of 5v5 goal scoring, and divided the game time into two-minute buckets. Here are the results:
Note that I've added two-unit moving average lines for each period.
As for corroborating/debunking Kelly Hrudy's theory, the beginnings of each period are the quietest times of all, so consider that half of the idea completely wrong. The beginning of the first period is, in fact, the most difficult time of all to score.
The ends of the periods, however, each show a distinct upturn. The most extreme example is, of course, the third period, when, presumably, many teams have their goalies pulled, and are desperately trying to tie a game.That said, the end of the second period is not a particularly likely scoring time, and the end of the first, although as likely as other points, isn't a bonanza of goal celebrations, either.
I haven't bothered to compare 5v5, 4v5, and 5v4 situations, but I do have overtime numbers:
Now, it's true that the last bracket is only one minute, since the final period is only five minutes long, the obvious trend to point out here is that most overtime goals come in the first two minutes of OT. Your guess is as good as mine as to why.
In summation, Kelly Hrudy isn't all wrong. He's definitely wrong about the beginnings of periods being important - OT aside - but the up-tick in goals at the end of the 1st, 2nd, and 3rd frames is definitely discernable. It's not as though it's a huge surge, but I can understand how observer bias could magnify this effect. Goals seem just as likely - if not more so - to come around the 2:00 - 8:00 mark.
So the next time an 'analyst' points out that the opening two minutes are among the most critical in the game for 'setting the tone' or that the final two minutes are in some other way more important, remember that goals come from all over the time sheet.