The luck of the puck in the Stanley Cup – why chance plays such a big role in hockey

A mathematical approach known as ‘true score theory’ can assess the contribution of luck to a team’s overall success. Bruce Bennett/Getty Images by Mark Robert Rank, Arts & Sciences at Washington University in St. Louis The NHL playoffs are almost like a second season – two months of bruising, relentless play, as the top teams compete for the chance to hoist Lord Stanley’s Cup. The 16 hockey teams that have made it into the postseason owe a great deal of their success to the abilities of their players and the tactics of their coaching staffs. They should also thank their lucky stars. In my new book “The Random Factor,” I explain why of the five major U.S. team sports – basketball, football, baseball, hockey and soccer – the one with the greatest amount of luck involved in wins and losses is hockey. Skill vs. chance Using a mathematical approach known as “true score theory,” analysts have been able to assess the contribution of luck to a team’s overall success. This statistical technique utilizes the variance in skill, chance and outcome to estimate the relative importance of skills versus chance in determining results. In the NHL, it is estimated that the...