Objective The reliability of a concussion symptom checklist can become compromised by external conditions (weather, medical conditions, stress, medications, etc.). This study assessed the day-to-day reliability of the SCAT3 Symptom Evaluation to determine if participants provide consistent responses in addition to determining the frequency and severity of the 22 symptoms in a non-concussed, adult, athletic population.

Design Repeated measure observational design.

Setting This study was conducted at a University in Ohio, U.S.A.

Participants 52 volunteers (18 to 30 years), self-identified as an athlete and had not suffered a concussion in the past 6 months.

Intervention Participants completed the SCAT3 Symptom Evaluation at prescribed times through the day over a 7 day period. Participants were randomly assigned to two equal groups, alternating between completing the SCAT3 Symptom Evaluation twice (at wake up and before bed) or once (in the afternoon) each day.

Outcome measures Severity and frequency of each of the 22 symptoms over a 7 day period.

Main results The single measure intraclass correlation coefficient was 0.496 (95% CI=0.382 to 0.620, SEM=0.134) for the frequency of symptoms and 0.438 (95% CI=0.325 to 0.568, SEM=0.221) for the sum of the symptom severity over 7 days.

Conclusions The results demonstrated poor day-to-day reliability for the reporting of the frequency and severity of symptoms. All of the 22 symptoms on the SCAT3 Symptom Checklist were reported by at least one participant with the most commonly reported symptoms being fatigue or low energy, drowsiness, and headaches.

Competing interests None.