Data for the first portion of the study include all participants who completed the NFHS/CDC online course since its inception (May 2010 to July 2013). Participant counts are presented by state and sports coached. To allow for easier comparison between states with different population sizes, we present state participation rates per 100 000 population using 2010 Census data. State population-based participation rates were calculated instead of subgroup-specific rates—such as coach or athletic trainer participation rates—because subgroup population sizes are unknown. For data presented by sport coached, we allow individuals to be counted multiple times, as participants could indicate that they coached more than 1 sport. Because many states and organizations require that persons affiliated with a high school sport complete a qualifying concussion course on a regular basis (eg, annually), some participants have completed the NFHS/CDC concussion course multiple times. Thus, we present results for both unique participants as well as total course completions (a single participant may be counted multiple times). Unique participants are identified on the basis of the e-mail address provided at registration.

The second portion of the study examines a subset of course participants with pre- and posttest results. Course participants take a 5-question pretest before starting the course and are required to pass a posttest (identical to the pretest) to receive a certificate of completion. Although these tests have been required since the course inception, responses were not recorded until fall 2012. Thus, this analysis includes only pre- and posttest results from November 2012 to July 2013. To examine knowledge gained from this course, we limit the pre- and posttest data set to registrants in the NFHS database that took the course for the first time during this timeframe.

The 5 test questions are included in Table 1, with the correct response indicated. To determine which questions are most discriminating in terms of knowledge change before and after the course, we calculate the percentage of participants who responded correctly to each question in the pre- and posttest.

For each participant, we calculate an overall score ranging from 0 to 100 for the pre- and posttest, on the basis of the percentage of correct responses (eg, a participant who answers all questions correctly receives a score of 100). To compare pre- and posttest results, we present the distribution of pre- and posttest scores overall. We also present the percentage of participants answering all questions correctly and the mean score by sex, self-identified primary role (eg, coach, student, and parent), and sports coached. We do not present tests for statistical significance because the large sample size (n = 133 764) would result in statistical significance of small differences, which do not necessarily indicate meaningful differences.¹⁵

Between its inception in May 2010 and July 2013, the NFHS/CDC online concussion course has been completed 819 223 times, reaching 666 026 unique participants, including residents from all 50 states and the District of Columbia (see Table 2). The largest number of participants is from Ohio (16%) and Massachusetts (12%). Massachusetts had the highest rates of participation, with 1238 participants per 100 000 population, followed by North Dakota, Ohio, Vermont, and South Dakota (see Figure 1). The lowest rates of participation were in New York and Illinois, with fewer than 25 participants per 100 000 population. Football was the most frequently reported sport coached among course participants, involving 146 616 participants (22%), followed by 87 262 from baseball (13%), 76 739 from boys basketball (12%), and 63 759 from girls basketball (10%) (see Table 3).

Among the 133 764 participants who completed the course for the first time during the data collection period, 2 of the 5 questions were answered correctly by more than 98% of participants in both the pre- and posttests (see Table 4). About 91% of respondents correctly indicated during the pretest that even a mild jolt can cause a brain injury, and this increased to 98% at posttest. A total of 86% of respondents correctly responded during the pretest that a concussion is a “traumatic brain injury that interferes with normal brain function,” which improved to 98% at the posttest. Finally, while only 24% of participants correctly identified the option that was least likely to decrease the risks of death or serious long-term problems from concussion in the pretest (correct answer: having magnetic resonance imaging), 62% responded correctly in the posttest.

The distribution of scores improved from pre- to posttests, with 21% of respondents answering all 5 questions correctly on the pretest and 60% answering all questions correctly on the posttest (see Figure 2). There were minimal differences in scores between men and women, but some differences by primary role, which was self-identified by the participant (see Table 5). For example, before taking the course, participants who identified as students exhibited the lowest levels of knowledge, with only 17% answering all 5 questions correctly on the pretest. Athletic trainers showed the most initial knowledge, with 41% answering all questions correctly on the pretest. Although participants from all roles showed improvement between pre- and posttests, students also had the lowest percentage of all questions answered correctly at posttest and athletic trainers had the highest percentage (48% and 69%, respectively). Among sports coached, spirit coaches (eg, cheerleading) had the lowest levels of initial knowledge, with only 17% answering all questions correctly in the pretest, whereas field hockey (34%) and ice hockey (33%) coaches had the highest percentage answering all questions correctly in the pretest. Differences by sport coached were smaller at posttest, with 55% to 66% answering all questions correctly.

This study is subject to a number of limitations. First, while these data allow us to assess knowledge gained immediately after participating in an online educational training, we are unable to assess knowledge retained over time, nor whether improvements in knowledge resulted in behavior change (eg, pulling athletes from play for medical evaluation). Second, knowledge is based on 5 questions, some of which most respondents answered correctly before taking the training. Future examinations with more rigorous questions may reveal important knowledge gains and gaps. To this end, the NFHS has added and altered questions for the pre- and posttest beginning in August 2013. Third, for many sports, coaches are requested or required to take the training prior to the start of their season. However, our examination of pre- and posttest scores did not include an entire year of data collection. Thus, our results may not be representative of sports with seasons starting between August and October (eg, football). Finally, if a participant registered and completed the course using multiple e-mail accounts, that person would have been incorrectly counted as multiple individuals.

This study had a number of strengths. It involved a large number of participants. It also documented the timely and broad reach of this online training, the representation of many high school activities, and the nationwide distribution of participants.