Over the past 10 years, all 50 states and the District of Columbia have passed new laws governing head injury protocol in youth sports. The majority of those laws include requirements for educating coaches, athletes, trainers and parents about the effects of concussions, removing young athletes from play following a concussion, and being cleared to play by medical personnel.

A new study published Thursday in the American Journal of Public Health used a nationally representative sample of data from 100 high schools for each year between 2005 and 2015 to explore the effectiveness of these laws, passed between 2009 and 2014, on a state-by-state basis and found a marked decline in repeated concussions among teens.

Researchers analyzed state-specific concussion data from before and after laws went into effect, and found a similar trend in each state. Immediately after the laws were passed, the number of concussions in each state increased, which the study attributes to improvements in reporting practices and a greater awareness of the gravity of head injuries.

Subsequently, the study notes a decline in concussion statistics in each state, starting around 2.6 years after individual laws were passed. Overall, the study found that high school student-athletes reported approximately 2.7 million concussions between fall 2005 and spring 2016, 11 percent of which were recurrent injuries.

Despite the improvements made in recent years to increase tracking data and return-to-play protocol for young athletes, researchers say enforcement and widespread data collection still fall short of the goal. Sports injury researcher from Nationwide Children’s Hospital and Ohio State University Ginger Jingzhen Yang also pointed out that the laws are not focused on prevention.

Yang told The Washington Post, “These laws focus on recurrence and education, which is important, but they don’t have prevention as part of the law, and that needs to be included. We need more strategies for minimizing body and head contact.”

Courtney Cameron is Editorial Assistant of Athletic Business.