Abstract
The object of this study was to investigate the effect of differences in format on the precision of teacher ratings and thus on the reliability and validity of two teacher rating scales of children's hyperactive behavior. Teachers (N=242) rated a sample of children in their classrooms using rating scales assessing similar attributes with different formats. For a sub-sample the rating scales were readministered after 2 weeks. The results indicated that improvement can be made in the precision of teacher ratings that may be reflected in improved reliability and validity.