The Dance Functional Outcome Survey (DFOS) is Reliable, Valid, and Responsive in Pediatric Dancers

The Dance Functional Outcome Survey (DFOS) is a dance-specific questionnaire developed for use with ballet and modern dancers at all training levels. To date, no study has assessed the psychometric properties of the DFOS in pediatric dancers. The purposes of this study were to determine: 1. the reliability of the DFOS when used with healthy and injured pediatric dancers; 2. the validity of the DFOS com- pared to a well-established generic scale, the Pediatric Quality of Life Inventory Physical Function Scale (PedsQL-PFS); and 3. the sensitivity and responsiveness to change of the DFOS in injured dancers. One hundred and two dancers completed the DFOS twice within 10 days. Intra-class correlation coefficients (ICCs) were used to assess test-retest reliability. In a sample of 148 dancers, construct validity was explored by comparing the DFOS to the PedsQL-PFS using Pearson correlations, and Exploratory Factor Analysis (EFA) and Cronbach's alpha were used for internal consistency analyses. A sub-set of 22 injured dancers was employed to examine responsiveness using repeated measures analysis of variance (p < 0.05). The DFOS demonstrated high test-retest reliability (ICC ≥ 0.90). The DFOS total score, activities of daily living (ADL), and dance technique sub-scores had strong construct validity compared to the PedsQL-PFS (r ≥ 0.79). Cronbach's alpha was high ( α = 0.92), indicating excellent internal consistency. There were significant differences across time in DFOS scores (p < 0.001), demonstrating responsiveness to change. There were no floor or ceiling effects. Thus, the DFOS demonstrates excellent reliability, strong validity, and good responsiveness over time and is a viable tool for assessing function in pediatric dancers.