Intra- and Inter-Rater Reliability of a Ballet-based Dance Technique Screening Instrument

OBJECTIVES: To investigate intra- and inter-rater reliability of a ballet-based Dance Technique Screening Instrument used by physical therapists (PTs) and student PTs (SPTs) with prior dance medicine or dance experience. METHODS: Ten pre-professional dancers were video-recorded in the sagittal and frontal planes while performing four dance sequences: 1) second position grand plie; 2) developpe a la seconde; 3) single-limb passe releve balance; and 4) jumps in first position. Dance videos and electronic versions of the demographics and scoring forms were provided through a secure online survey to 28 PTs and SPTs who served as raters. Raters reviewed a training video prior to scoring the 10 dancers. Raters were asked to repeat their assessments 1-2 wks later. Intraclass correlations (ICC) were assessed for all-raters, PTs, and SPTs for total and sequence scores. RESULTS: Twenty-eight raters assessed the videos one time. Inter-rater reliability was ICC=0.98 (CI35 =0.96-0.99) (all-raters), with PTs and SPTs displaying similar values (ICC=0.96 and 0.96, respectively). Eighteen raters (11 PTs, 7 SPTs) repeated the video analysis. Intra-rater reliability was ICC=0.78 (CI95 =0.72-0.83) with PTs ICC=0.81 and SPTs ICC=0.70. CONCLUSIONS: Correlations were high for all-raters. SPTs were as reliable as PTs in inter-rater comparisons. PTs exhibited higher intra-rater reliability compared to SPTs. These results substantiate the reliability of a standardized testing instrument to conduct dance technique assessment. Validity of this instrument was demonstrated in a previous study which found dancers with better technique were less likely to sustain injury. The ability to identify technique deficits can guide preventative programs that may reduce injury risk.