Comment on Tarnowski, Prinz, and Nay (1986): No Evidence for Differential Diagnostic Validity of Attention Deficit Disorder With Hyperactivity (ADDH)

Tarnowski, Prinz, and Nay (1986) reported data they claim supports the differential diagnostic validity of attention deficit disorder with hyperactivity (ADDH). However, neither the multivariate nor univariate analyses reported by Tarnowski et al. provide any evidence to support this conclusion, because the only significant effects were obtained in comparisons between disordered and nondisordered groups (or groups that included nondisordered children) rather than comparisons within disordered groups.