.Valid inferences about the efficacy of treatment trials require high-quality outcome measures that meet rigorous measurement standards. The present study was conducted to analyze reliability and validity issues in both the Mini-BESTest and the BBS and to compare their responsiveness after a 10-session physical therapy program for balance disorders. Our results are in line with the recent literature13,18,19 and indicate that the Mini-BESTest shows sound psychometric properties, which compare favorably with those of the BBS, particularly when measuring change at the individual level.