Examining the Use of Head Impact Sensors in School Sports

Prepared for
Mathematica Policy Research
Two football helmets on field


To help researchers and policymakers identify the best ways to prevent concussions among young athletes, Mathematica conducted a pilot project to explore the experiences at two high schools that outfitted athletes with head impact sensors. Head impact sensors are used to measure the g forces athletes sustain during contact in sport. Although these sensors cannot determine whether or not the athlete sustained a concussion, they serve as a promising tool for research.

Through interviews with school principals, coaches, and parents as well as focus groups with young athletes, we developed a greater understanding of the potential of head impact sensor technology to improve player safety. Key findings include the following:

  • Sensors could reduce the risk of concussion. Parents reported that their children were more aware of brain injury as a result of the sensors’ presence. And students at one school reported greater awareness of their tackling technique because of concern that the sensor might record a heavy-impact reading and result in their removal from the game.
  • A sound plan is necessary for implementing the sensors. Any school implementing the sensors must have a plan to manage and address logistical and troubleshooting issues as well as a plan for collecting and using the sensor data. How will the school use the data? Who will review the data? With whom will the school share the data?
  • Sensors are not diagnostic tools and should not be used as such. These devices cannot determine whether athletes sustained a concussion, and there is currently no valid clinical standard for integrating these sensors with other clinical tools. However, both pilot schools used the sensors in a pseudo-diagnostic fashion. For example, one school set a threshold for mandatory evaluation of a student if an impact was recorded at 70 g and above; the other school set the threshold at 90 g and above. This confused parents and students at both schools who believed any recorded impact above these thresholds meant the student had experienced a concussion. Although it might seem logical that a higher g-force hit increases the risk of concussion, brain injury can occur even at low g-force levels.

Head Sensor Visual Project

In a separate initiative, Mathematica obtained a large de-identified data set containing head impact sensor recordings experienced by high school football players. These recordings provided the g force experienced by an athlete after an impact. This data visualization captures the cumulative number of hits endured by a high school linebacker across all practices and games in one season. The green dots represent a low level of g-force impact, the yellow dots represent a moderate impact, and red dots represent the most severe impact. This visual helps stakeholders to understand the physical mechanism of motion and cumulative effect of hits experienced by a high school football player.