Objectives : To provide further evidence of the test—retest reliability and agreement of the Movement Assessment Battery for Children (M-ABC), a standardized motor test used for identification and evaluation of children with mild to moderate motor impairment. Both the stability of total test scores and classification according to specified cut-off points were examined.
Design and setting : Children were tested on the M-ABC, three times with an interval of three weeks between each assessment.
Participants : Thirty-three 4- and 5-year-old children with poor motor performance, 24 boys and 9 girls.
Results : A systematic practice effect between three consecutive testing sessions was shown. This was significant for the total score and two of the three subscores. Test—retest reliability of the total test score yielded an intraclass correlation coefficient (ICC) of 0.88. The total impairment score ranged between 0 and 40. The standard error of measurement (SEM) of this score was 2.4, resulting in a least detectable difference of 6.6 (with alpha set at 5%). The agreement over three testing sessions (κ) was 0.72.
Conclusions : The total impairment score of the M-ABC is a reliable measure for identification of mild to moderate motor impairment in young children. Repeated testing on the M-ABC at intervals of three weeks results in a systematic measurement error and is not recommended. The SEM is substantial. Follow-up of preschool children with the M-ABC as a single outcome measure is not appropriate.
