Concussion incidence rates with 95% prediction intervals by sport

Incidence rates and 95% prediction intervals plotted by sport. Prediction intervals below 0 were truncated at 0. Sports were grouped into risk categories based on k-means of rates. Group 3 sports, which include rugby, American football, and ice hockey, represent the highest-risk group, followed by groups 2 and 1. Football and wrestling were male-only sports while field hockey, gymnastics, and cheerleading were female-only sports.