Teachers' ratings of gross motor skills suffer from low concurrent validity.

In this study an attempt was made to construct a reliable and valid unifactorial teachers' rating scale for gross motor ability. Study 1 (132 children from 3 to 7 years) revealed that reliability of the scale was acceptable and that the scale represented an unifactorial dimension. Two studies on concurrent validity of the scale with an experimental gross motor task (stepping-stone crossing), the unifactorial subtest Locomotion of the Test of Gross Motor Development and the subtest Balance of the Movement Assessment Battery for Children as criterion measures, did not produce acceptable validity coefficients. In both validation studies an age effect was found. It was concluded that factor specificity does not seem the answer to the usual low validity coefficients of multifactorial teachers' rating scales. An alternative approach is suggested in which the assessment of functional activities in daily situations is stressed. Finally, the inclusion of atypical groups in random samples, which is common practice in research on concurrent validity of screening instruments for children's motor problems, is discussed.