Interrater Reliability of the Observable Movement Quality Scale for Children

The authors investigated the interrater reliability, the standard deviation of the random measurement error, and the limits of agreement (LoA) of the Observable Movement Quality (OMQ) scale in children. Movement quality is important in the recognition of motor problems, and the OMQ scale, a questionnaire used by paediatric physical therapists, has been developed for use with an age-specific motor test to observe movement quality and score relative to what is expected for a child's age. Paediatric physical therapists (n=28; 2 men, 26 women) observed video-recorded assessments of age-related motor tests in children (n=9) aged 6 months to 6 years and filled in the OMQ scale (possible score range 15-75 points). For our analyses, we used linear mixed models without fixed effects. The interrater reliability was moderate (intra-class correlation coefficient [ICC_2,1]: 0.67, 95% CI: 0.47, 0.88); neither work setting nor work experience exerted any influence on it. The standard deviation of the random measurement error was 5.7, and the LoA was 31.5. Item agreement was good (proportion of observed agreement [P_o] total 0.82-0.99). The OMQ scale showed moderate interrater reliability when being used by therapists who were unfamiliar with the questionnaire and who had received only 2 hours of training. Feedback from the participants suggested a need for more comprehensive training in using the OMQ scale in clinical practice.