Structural validity of the Movement ABC-2 test: factor structure comparisons across three age groups.

BACKGROUND

The Movement ABC test is one of the most widely used assessments in the field of Developmental Coordination Disorder (DCD). Improvements to the 2nd edition of the test (M-ABC-2) include an extension of the age range and reduction in the number of age bands as well as revision of tasks. The total test score provides a measure of motor performance, which can be used to help make a diagnosis of DCD. M-ABC-2 also provides 3 sub-scales for Manual Dexterity, Aiming and Catching and Balance but the validity of these conceptually derived sub-scales has not previously been reported.

AIM

To examine the factor structure of the M-ABC-2 test across the three age bands (AB): AB1 (3-6-year olds), AB2 (7-10-year olds) and AB3 (11-16-year olds).

METHOD

Data from the 2007 standardisation sample (N=1172) were used in this study. Confirmatory factor analyses (CFA) and structural equation modelling (LISREL 8.8) were employed to explore the relationship between the tasks within each of the 3 age bands. A model trimming approach was used to arrive at a well fitting model.

RESULTS

In AB1 a complex factor structure emerged providing evidence for an independent general factor, as well as specific factors representing the 3 test components. In AB2 a final model emerged with four correlated factors, an additional distinction being drawn between static and dynamic balance. In addition, a 2nd order general factor explained a considerable amount of variance in each primary factor. In AB3 CFA supported the 3-factor structure of the M-ABC-2, with only modest correlations between each factor.

CONCLUSIONS

The confirmatory factor analyses undertaken in this study further validate the structural validity of the M-ABC-2 as it has developed over time. Although its tasks are largely associated with the three sub-components within each age band, there was also clear evidence for a change in the factor structure towards differentiation in motor abilities with age.