The ADHDT is an effective instrument for identifying and evaluating attention-deficit disorders. The ADHDT contains 36 items that describe characteristic behaviors of persons with ADHD. These items comprise three subtests representing the core symptoms necessary for the diagnosis of ADHD: hyperactivity, impulsivity, and inattention. Normed in 1993 and 1994 on a representative national sample of more than 1,200 persons who were diagnosed with attention deficit disorders, the ADHDT studies of internal consistency and test-retest reliability produced high (.90+) coefficients.
