Parental ratings of overactivity are unrelated to teachers\u27 ratings of overactivity or to laboratory measures of inattention. Teachers\u27 ratings of overactivity correlate strongly with teachers\u27 ratings of inattention as well as to laboratory measures of inattention. Teachers\u27 ratings of inattention, however, are unrelated to laboratory measures of inattention when IQ is controlled. There are considerable definitional problems relating to the symptoms of hyperactivity and inattention, making it difficult create a behavioral definition of the psychiatric syndrome of attention deficit disorder