Forty-four items of a Nurses Behavior Chart used at the Phipps Psychiatric Clinic of Johns Hopkins Hospital were factor analyzed, based on a sample of 100 schizophrenic patients. Ten orthogonal factors which were extracted indicated the dimensions of schizophrenic illness. Five of these factors (based on 14 behavior items) provide an index of treatment change which is highly significant when compared with clinical judgment of improvement. The index has clinical and research potential.Abstract Teaser