Intra/interrater reliability of measurements on body posture photographs

Intra/interrater's reliability of the coordinates of ten anatomical landmarks on a frontal and a dorsal body posture photograph of 18 subjects was tested. The measurements were conducted by two testers with an interval of seven days between each session. The repeated measurements of each examiner (intrarater) and the first and second measurement of both examiners (interrater) were assessed for reliability. Statistical testing was performed to confirm the data to fit a normal distribution according to Shapiro-Wilks (alpha = 0.05). Intraclass correlation coefficients and Pearson Product-Moment correlation coefficients were used to assess reliability at the alpha level of 0.05. Pearson's correlation coefficients were between 0.72 and 1.0, Intraclass correlation coefficients (ICC) between 0.66 and 1.0. In further analysis of the results, repeated-measures paired T-tests were used to test for differences between repeated measures. After adjustment of the alpha level for the total number of comparisons, 10 of the paired T-tests were significant (2 intra; 8 inter). The results indicate that the measuring method provides reliable data and that two different test modes produce consistent measurements.