It’s NHL playoff season, which means that, given the relative league parity, every call and no-call comes under a microscope. In the third period of close games, for example, a penalty call alone can decrease a team’s chance of winning by 10 percentage points or more.
One characteristic of NHL games that a few prominent members of the media have picked up on is that penalty calls tend to “even-up” within a game – that is, it is unlikely that either team ends the game with a substantially larger number of penalties than its opponent.