PURPOSE: To investigate the inter-rater and intra-rater reliability and calculate the Balance Error Scoring System (BESS) minimal detectable change among certified athletic trainers in a population with acute concussion.

METHODS: Sixteen certified athletic trainers scored BESS videos of student-athletes with acute concussion on two occasions 1 week apart. The inter-rater and intra-rater reliability values and minimal detectable change scores were calculated for the two viewings.

RESULTS: The inter-rater reliability was 0.75 and the intra-rater reliability was 0.86. The inter-rater and intra-rater minimal detectable change scores were 11.3 and 8.6 errors, respectively.

CONCLUSIONS: The reliability values were moderate to good, but the minimal detectable change scores were higher than those previously reported for healthy participants. Importantly, the minimal detectable change scores in the current study exceed the normal change reported for BESS performance (4 to 6 errors) after concussion.