A total of youth football helmets have been rated using the STAR evaluation system. Our impact tests evaluate a helmet's ability to reduce linear and rotational acceleration of the head resulting from a range of head impacts a youth football player might see on the field. Our lab tests are based on data we collected directly from 10 to 14 year old youth football players that wore helmets equipped with sensors. Helmets with more stars provide a reduction in concussion risk for these impacts compared to helmets with less stars.