Wednesday, September 7, 2011

Luck, Skill and Sample Size in Playoff Shooting Percentage

In a discussion on a message board about my previous article on luck and skill in shooting percentage, someone asked about the numbers for the playoffs. The average series runs a little under 6 games. That makes the entire playoffs pretty close to a quarter of a season for the teams that make the Cup finals. Here are the numbers for how often the team that shoots at a higher percentage (about 7th best in the league) outshoots the team that is bad at shooting (~7th worst in the league):

Time periodNumber of ShotsA scores moreB scores moreGoals scored equalA > B SignificantB > A significant
Four Games9651%38.1%10.9%7.4%3.9%
Five Games12051.9%38.7%9.4%7.6%3.8%
Six Games14454.1%37.5%8.4%7.8%3.4%
Seven Games16855.4%36.6%8%7.9%3.1%
Second Round27457.4%36.6%6%9%3.1%
Conference Finals41160.5%34.6%4.9%9.4%2.7%
Stanley Cup Finals54862.9%33.1%4%10.7%1.9%

Something worth noting is that on average this gap in shooting from good to bad is worth a little less than a goal (0.88 goals) per series. Despite that, the team with less shooting talent still has between a 35% and 40% chance to get more goals at even strength in a series if they get the same number of shots, and another 8-10% shot at breaking even. The bounces don't always even out. That leaves a lot of room for luck, creating more shots and special teams.


  1. But I thought it's a fact that "the bounces even out over the course of a seven-game series." Clearly, your data are wrong :)