Is the Movement Assessment Battery for Children-2nd edition a reliable instrument to measure motor performance in 3 year old children?

Formal testing of 3 year old children is a new feature in the revised version of the Movement Assessment Battery for Children (Movement ABC-2). Our study evaluated the reliability and explored the clinical applicability of the Movement ABC-2 Test in this young age group. A total of 50 typically children were given two trials of the test within a one to two week interval by two physical therapists: same assessor (n = 28 children) and different assessors (n = 22 children). Psychometric properties were evaluated by calculating internal consistency (Cronbach α), intra-class correlation (ICC), the standard error of measurement (SEM), the smallest detectable difference (SDD) and Kappa values for classification agreement. The results are promising for future implementation of the Movement ABC-2 in clinical practice. The children's performance was highly reproducible when tested by the same assessor (ICC .94) The SEM was 1.7 or 2.1 standard scores for 90% or 95% confidence intervals respectively, making the test sensitive enough to detect individual changes. If two different assessors tested the children the ICC was .76. In conclusion, the revised test can be applied to assess motor performance in typically developing 3-year old children. Future studies are needed to confirm if the same can be said for children with motor delays.

Research highlights
► Three year old children can be formally and reliably tested (ICC .94).
► Movement ABC-2 is sensitive enough to detect individual changes.
► The minimal change in total test score between two test occasions needs to be at least 1.7 higher or lower before one may conclude that a child has really improved or worsened (90% CI).
► Replacing failed items by lowest score possible does not deflate the reliability of the component or total scores (range .74–.85)