The study, involving 100 children (11 and 12 years old), was designed to generate descriptive data regarding the behavioral and psychometric characteristics of exceptional children in the public schools. A review of the literature revealed that it is difficult to make a differential diagnosis among educable mentally retarded (EMR), emotionally disturbed (ED), and learning disabled (LD) students when behavioral and psychometric characteristics of each group are considered. Limited empirical research has been undertaken to quantify similarities or differences in the characteristics of these categories of exceptional students in the public schools. Five groups of Ss (20 EMR, 20 ED, 20 LD, 20 at-risk, and 20 normal) were directly observed in the public schools and were assessed by commonly used psychometric measures. The latter two groups served as controls to evaluate the effectiveness of the behavior observation procedure and to serve as comparison groups for the observational procedure and the psychometric test battery. Teams of observers and certified psychometricians collected behavioral and psychometric data in 22 elementary schools. Results indicated that the exceptional, at-risk, and normal students did not differ in behavioral characteristics. However, data suggested that exceptional children showed lower frequencies of non-task oriented behavior and higher frequencies of task oriented behavior when placed in special education resource rooms. Cognitive, achievement, self concept, and visual-motor measures were administered to all groups. Results suggested that exceptional children do not differ among groups on achievement, self concept, and visual-motor measures. At-risk and normal Ss generally yielded significantly higher scores on all psychometric assessment devices. Findings of the investigation with regard to the labeling and placement of exceptional children in special education programs were discussed. Also considered were the efficacy of special education resource room programs, noncategorical special education models, and implications for teacher preparation. (Author/SW)